How to Find the Domain of Any Function (NancyPi)

Published on May 15, 2018 by

MIT grad shows a surefire way to find the domain of any function. To skip ahead: 1) For POLYNOMIAL only, skip to time 0:45. 2) For FRACTION only, skip to time 1:44. 3) For SQUARE ROOT only, skip to 5:08. 4) For SQUARE ROOT ON BOTTOM of Fraction, skip to 8:44. 5) For SQUARE ROOT ON TOP of Fraction, skip to 10:09. Nancy formerly of MathBFF explains the steps.

For how to SOLVE QUADRATIC equations by FACTORING, jump to:
For how to SOLVE INEQUALITIES, jump to:

Follow Nancy on Instagram!

For Domain, you just need to watch out for Square Roots and/or Fractions!

If your function is...

1) a POLYNOMIAL (no square roots or fractions), i.e. f(x) = x^2 + 3x + 1, domain is "all real numbers."

2) a FRACTION (w/ no square root), i.e. f(x) = (2x+1)/(x^2+5x+6). Set bottom "not equal" to zero. Solve for x.

3) a SQUARE ROOT (w/ no fraction), i.e. f(x) = sqrt(x+1). Set part under root "greater than or equal to zero".

4) a FRACTION w/ A SQUARE ROOT ON BOTTOM, i.e. f(x) = (x^2+2x+3)/(sqrt(x+1)). Set part under root "greater than zero." Solve the inequality. NOTE THE DIFFERENCE: You must set it greater than zero, not "greater than OR EQUAL TO zero" because we can't have zero (or square root of zero) in the denominator.

5) a FRACTION w/ A SQUARE ROOT ON TOP, i.e. f(x) = (sqrt(x+1))/(x^2+4), i) Set the bottom "not equal to" zero & solve; ii) Set what's under the root "greater than or equal to zero" & solve; iii) Take intersection of your two solutions.

For more of my math videos, check out:

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  • Terra Netti 5 years ago

    First like!

  • Abhishek Mukherjee 5 years ago

    Thanks! Alot

  • Mohammad Ali 5 years ago

    Thanks ❤️

  • James Dashwood 5 years ago

    Marry me and do my math for the rest of our lives.

    • Carlos Craigito 4 years ago

      James Dashwood
      So what I have figured out is, u have a problem with short forms, and u like to hit on teachers. End of convo

    • kc koellein 4 years ago

      This was hilarious, actually.

    • SoosUnknown 4 years ago

      Im so confused on what was being argued

    • David Park 4 years ago

      @SoosUnknown sounds like james has a problem and it doesnt involve math lol

    • nick ambrose 4 years ago


  • Maria das Santos 5 years ago

    Fantastic Nancy is BAACK!

  • daniel gallen 5 years ago

    “You don’t have to like math… but you can like my video.”
    Smooth. I like it. 👍🏻

    • Mike Keenan 5 years ago

      I actually like math, and I still liked the video.

    • Grace T. Haokip 3 years ago

      daniel gallen 🤣🤣🤣🤣🤣i was laughing so hard in tht part .. she has some humour 🤣

    • pavel mihai 3 years ago

      Nice Video clip! Sorry for chiming in, I am interested in your thoughts. Have you heard about – Nanmily Domain Demythification (should be on google have a look)? It is a smashing exclusive guide for finding success and profit using this online traffic source without the headache. Ive heard some awesome things about it and my mate after many years got excellent results with it.

  • Daniel Lassander 5 years ago

    I love this channel, an intelligent and also attractive woman showing me how to do math 🙂

    • menkeyman 4 years ago

      I have to disagree with you Daniel, she is not attractive, she is mesmerizing. I have no idea what she said after “Hi!”, but I watched the video 5 times and still can’t remember what she said.

    • Indiegirl007 4 years ago

      Ya’ll are so thirsty.

    • Ghaspus 4 years ago

      Just take the damn lesson

  • Windows Logo 5 years ago

    Do i need to check for 0 ^ 0 in any way??pls answer.

  • Deep Sadhu 5 years ago

    You looks like my ex.

  • Abel Lopez 5 years ago


  • amty 5 years ago

    nancy is fancy

  • shayna5445 5 years ago

    I’m so glad I found your new channel!! love you Nancy!! you’re the math MVP!

  • Neelpritam Lahon 5 years ago


  • Wrath Vengeance 5 years ago

    What should I do if there’s a quadratic on both numerator and denominator?

    • Ulises Castro 5 years ago

      It is the same first example explained by Nancy. It Doesn’t matter the numerator. The restriction is made by denominator because if it’s equal to zero, the expression becomes undetermined. I hope to be clear enough.

    • Jefferson Giann Ebal 5 years ago

      How do you find the range of a rational function whose numerator and denominator are in quadratic form? Ulises Castro

    • Ulises Castro 5 years ago

      Hi Jefferson. As I said before the funtion is restricted only by denominator. What is the range in a simple polynomial function?

  • Montreal Math and Physics Tutoring 5 years ago

    Hi Nancy.
    I believe videos like this is the main reason why so many students are failing math tests, and the internet is full of these. And of course the fault is not only from the creators since we all want to be popular and have views and subscriptions and we have to produce videos that students find “easy” to follow. That is exactly the biggest trap for students, because their exams are much more difficult and complicated that these examples and of course by the time they realize that it is too late. I think the first and most important part the student has to learn is a comprehensive methodology on how to approach any problem in the topic.

    • Jeffrey Alvarado 4 years ago

      Well, I don’t want to learn new concepts with a long overly complicated problem. So don’t hate.

    • Montreal Math and Physics Tutoring 4 years ago

      First of all I don’t hate. And second I don’t think you understood my comment. I didn’t write anywhere that you have to start a new topic with a complicated example. I just say that an introduction to a new concept should start with a general approach of solving any problem in the topic and not with an example (complicated or not).

    • Feer O 4 years ago

      Montreal Mathematics and Physics Tutoring
      I understand what ure saying. A lot of math videos on youtube are just basic solving problem of the topics. During exam, the question is beyond that. The great videos to watch is i think solving past exam papers.

    • Cade Sumner 4 years ago

      dude come on i know your upset because now people are coming here and not to the real tutor . this girl has the best videos and the only reason i am passing math right now. BACK OFF

    • SwagKing Ish 4 years ago

      stop hatin on her

  • Aliza roy 5 years ago

    Fantastic 😍

  • Juhi Gupta 5 years ago

    and for logarithmic function?

  • InfoTechVids 5 years ago

    Thank you very much. It helps me a lot😁

  • poody faisal 5 years ago

    Why u sad

  • Krishan Sharma 5 years ago

    Nice mam

  • Dasi Reddy Rohit Reddy 5 years ago

    Why is Nancy that sad, have some happiness in life

    • Tib Khan 4 years ago

      I’M SAYING. She looks like she’s about to cry

  • mi mic 5 years ago

    Umm. I have a question. How to find the domain if the expression is x^2 + y^2 = 1?

  • Pradeep Choudhary 5 years ago

    for trigonometric function and log ????

  • Benedict Maddara 5 years ago

    NANCYPI? haha cute <3

  • Gabrielle Joshebed Abarico 5 years ago

    Can you make a video of “how to find the range of any function”?

    • TheHardTruth 4 years ago

      I mean u can inverse the function and then find the domain of that.. That will be the range of f(x) function…

    • Kishore Subramani 4 years ago

      @TheHardTruth yes thank you

    • Mahnoor Waseem 4 years ago
  • Josue vargas 5 years ago

    Great video !!

  • Binibining Athea Niña Venus Basong 5 years ago

    Very well explained but how about range?

    • Javie Mike 4 years ago

      ikr wala akong mahanap na vid nya about range. loved her vid tho

  • Music Sorcerer 5 years ago

    Very hot

  • Sahashra Samarakkody 5 years ago

    Useful 100%

  • Blake Collins 5 years ago

    On the square root only section you have X^2 + 5X + 6. That factors into (X +3)(X + 2). Now you only flip an inequality sign when you divide or multiply by a negative number, which this problem doesn’t require. So you end up with: X >= -3 or X >= -2. So I don’t understand how you got X <= -3.

    • jason andreas 4 years ago

      it go me worried too, u are right

    • Julia Jubac 4 years ago

      you equate both equation by zero and solve forx, that’s how you can get the values

    • Denny Guevara 4 years ago

      Exactly what i was thinking too

    • Caileán Jones 4 years ago

      She is correct. Plot a graph of y = x^2 + 5x + 6 and you will see it cuts the x-axis at -2 and -3. Since we are dealing with >= 0, we need to see where the graph is above the x-axis. The graph is always above the x-axis when x<=-3 and x>=-2. Hope this helps 🙂

    • Akhil Goyal 3 years ago

      Hmmm…. Same problem

  • Jefferson Giann Ebal 5 years ago

    How do you find the range of a rational function whose numerator and denominator are in quadratic form?

  • Alex Xu 5 years ago

    Thank you for posting this video. I was studying this subject on Khan Academy, and when I did not understand, Sal went to fast for me. You go at the perfect pace so I can absorb everything.

  • mouloud benmaiza 5 years ago

    You are really cool and sexy

  • Yemi Abadariki 5 years ago

    But how do you solve questions with cube root?

  • Meeran Fazil 5 years ago

    How about finding the Range?

  • Poorman ASMR 5 years ago

    ur th e best teach erh n EVERSL!!!!!!!!!!!!!!!!!!!1 :Dddddddd

  • Moses Mwaura 5 years ago

    math bff

  • Di Wang 5 years ago

    Love you Nancy! You saved me from stupit college placement!

  • wolfie julie 5 years ago

    I love her pink whiteboard pen …lmao ❤

  • Magsoul April 5 years ago

    Thank you so much, this helped a lot. I stayed up all night trying to find an answer to finding the domain of a function.

  • Glenn D. Merabe MrAltheagwen 5 years ago

    hi nancy love you

  • Jared Calub 5 years ago


  • kimaya panash 5 years ago

    ohh now that i have learned this topic from you i am gonna make my friends beg me to teach them…love you so much for teaching me this

  • Mazhar Abbas Bukhari 4 years ago

    oh God ,Thats why i was always confused in finding domain,even did not attempt the question in exam…though i got the idea,but still stumbling.

  • Mazhar Abbas Bukhari 4 years ago

    Miss Nancy ,really are you sure about second problem solution of 3rd type (Square root )….i m confused about why -2 remain at greater than or equal while -3 become lessthan or equal …like how ??? any body else can …

  • Rajeev Kumar 4 years ago

    I think am confused of your solving maths

    • Feer O 4 years ago

      Rajeev Kumar
      Here she solved them briefly. You should check other video for more details on how she get this and that.

  • Gabriel Ethan 4 years ago

    Can you also do a video on how you find range of any function?

    • Gabriel Ethan 4 years ago


    • wtf 3 years ago


    • wtf 3 years ago

      I need a video on range I don’t get it, I guess you could go the inverse of domain and then obtain the range however I’m sure there is an easier way

  • Hiede Nisperos 4 years ago

    why theres no negative examples? its always positiveee. should i contrary?

  • Emily Fish 4 years ago

    someone prove she isn’t a robot

  • Trade Monkey 4 years ago


  • sunchy.from.poland hihi 4 years ago

    Very simple way of explaining. Thanks!

  • Sharath SH 4 years ago

    You hand looks weird in the thumbnail.

  • Rudy 4 years ago

    now i need the range

  • dreamer achiever 4 years ago

    Does she writes in mirror image

  • Priscilla Nava 4 years ago

    Love you Nancy! Your my number 1 math guru 🙂

  • Danny 4 years ago


  • Daniel Diaz 4 years ago

    What if you have a cubed root on the bottom? Like if it’s 1/ x³+x

    • Becky S 3 years ago

      Set the radicand > 0 and solve. So x(x^2 + 1) > 0, critical value is only 0 since x^2 + 1 is always positive. So x > 0 is domain.

  • Kumasi máni 4 years ago

    Thank you way better then all those old videos!

  • Maraoo S 4 years ago

    Can you also do a video of how to find the range would help a lot

  • ulissitos 4 years ago

    Is she writing on a mirror???

  • Oscar Lazaro 4 years ago

    “]” would go after infinty because infinity is not a number

  • Esli Mensah 4 years ago

    this… this… this is talent… writing backwords??? this girl deserves a noble peace prize

    • Skullrak 3 years ago

      @Ameena no you are dumb. she writes with her right hand then flips the image

    • Pranamya Pradeep 3 years ago

      Have you guys never heard of learning glass

    • Ameena 3 years ago

      @Pranamya Pradeep THAT EXPLAINS IT!!!! Thank you!!

    • Pranamya Pradeep 3 years ago

      @Ameena you’re welcome!

    • Carbon Dioxide 3 years ago

      Im crying 💀😭😭😭

  • Stephanie R 4 years ago

    My wife 😍

  • Anand Alagu 4 years ago

    Pls make video of finding the range pls pls pls pls nancy mam

  • Bruce 4 years ago

    I like how she does not babble and erase. Her vid is thought-out and straight to the point.

  • Ethan F 4 years ago

    perfectly paced video, doesn’t take too long to talk about everything and very informative

  • G jangir 4 years ago

    Fantastic and amazing you’re method

  • Jayden Rose 4 years ago

    I love how she can do math backwards and write backwards she really deserves a price, also your video helped me out a lot. Keep the good work going. (2k18 september anyone)

    • aamin ali 4 years ago

      Divine Wolf the video is flipped she is actually writing backwards…

  • pp 4 years ago

    I wish my high school pre-calc teacher made it this clear…now I get it!

  • Juliet Porter 4 years ago

    My savior

  • Stride 4 years ago

    Like if you’re here from ms. Upsher 😩

  • XAMMIEE SA LEE 4 years ago


  • itsKiff 4 years ago

    Can someone help me at 5:49 minute, she says you need it to be greater than or equal to 0. So let’s say I have x-3 under the square root would it still have to be greater than or equal to 0? Or would i have to add x-3=0 x > or equal to 3 ? Because under the square root line I have x – 3 instead of x + 3

  • Gabriel Ethan 4 years ago


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    • Emmanuel Roland Rocco Bayoco 4 years ago

      My exams due tomorrow lol

    • YouKilled MySon 4 years ago

      just inverse the function (let function=y method) and find the domain of the inverse, because domain of f(x) inverse= range of f(x) and vice versa.

    • Anirudh 4 years ago

      @YouKilled MySon could you maybe link a video or article explaining how to do that?

    • Anirudh 4 years ago

      @YouKilled MySon so you take the inverse functions domain and I that is the normal functions? And the function must be one to one?

    • YouKilled MySon 4 years ago

      @Anirudh yeah

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  • menkeyman 4 years ago

    Nancy, I don’t like your videos, I love them, and you even more. I clicked on the Like, and Subscribe buttons, but for the life of me, I cannot find the marry button.

    Your servant and follower,

  • tee efren 4 years ago

    most math teachers arent attractive as you are

  • Briana Hernandez 4 years ago


  • Walaa Alnabhan 4 years ago

    You’re amazing teacher

  • علي شطا 4 years ago

    ? How do you find the algebraic range

  • Jessie G 4 years ago

    Wow she’s way more comprehensive than my maths tutor

  • Silas Mwaniki 4 years ago

    Haaah! Big thanks Ma

  • zaman 4 years ago

    u are great really. I love your method of teaching. love u dear so……….. much

  • Denise M. 4 years ago

    Very nice

  • Rrxxx310 4 years ago

    OMGGGGG I’ve been trying to understand domain since the beginning of the year thank youuuuuu ❤️

  • Stanley Agina 4 years ago

    How much can I thank you 👏👏👏👍

  • Dark Soul 4 years ago

    U So cute I’m actually interested 😂

  • Jeff Shiu 4 years ago

    Super helpful!

  • Ady Loy 4 years ago

    how about f(x)=x^2 – 9? what should i do?

  • MyName Hero 4 years ago

    Thanks alot mam this video really help me alot.hope to learn more from you

  • Ammar AlShaar 4 years ago

    Love u nancy been watching ur vids since 2015

  • Evie Brechler 4 years ago

    Literally all my math makes sense now

  • Eslam Saeed 4 years ago

    This is function come with my first exam in my faculty

    • [R] 4 years ago

      Eslam Saeed
      Domain is (-2, 2)

  • Jay 4 years ago

    Unfortunately, the problem with this video is that you used x+1 through the entire process of square root functions, I didn’t learn anything because you showed me how x+1 has to be greater than or equal to 0 three times. Next time you can use a more complex square root function? Besides that great video.

  • Bashar Naimi 4 years ago

    You’re awesome!

  • L C 4 years ago

    You’re a Prophet, praise the Number Gods

  • Roxanne Desjarlais 4 years ago

    wait, why was X^2 all real numbers? was it because of the square?

  • Amirul Haqim Mohd Jora 4 years ago

    definitely mirrored

  • FacCa Flame 4 years ago

    the times i screamed “I love you” after finishing one of your videos are just creapy 😂😂😂😂

  • Hella Hello 4 years ago

    nancy is mad sexy

  • lil diva 4 years ago

    You made this so easy, thank you so much 😭

  • Ahmed The kid 4 years ago

    I like how she broke up the different types of questions we can get

  • Charles Gangmeih 4 years ago

    Here from India 😜

  • Kogulan Murali 4 years ago

    Well Explain

  • TTV Ur Mom 4 years ago

    You’re left handed.

    • christian smith 4 years ago


  • Manveen kaur 4 years ago

    left hander!

  • B 4 years ago

    Life saver! Thank yooooooooooooooooou!

  • Paul Ps 4 years ago


  • Muhammad Saad Feroz 4 years ago


  • Aziath 4 years ago

    Can u teach us how to do our taxes

  • Tahj Alex 4 years ago

    7:48 how is x less than or equal to -3 ???

    • Punch 4 years ago

      Someone please answer because I’m wondering the same thing

    • Gui af 4 years ago

      X is squared

    • edward9296 4 years ago

      i did pq formel and only got +- -2.5 did i use wrong way to solve the equation

    • dontlie 4 years ago

      IDK if im late but when you solve the problem, you get (x+3)(x+2), then you solve for X for each one, x+3 = 0 —–> x = -3, x+2 = 0 ——> x= -2.

  • tupac shakur 4 years ago

    you’re hot.

  • Roysa Adeyemi 4 years ago

    The video is so well explained

  • more on youtube 4 years ago

    Please upload the video for finding range of any fuction

  • albert ma 4 years ago

    Dang, it is so hard writing back words

  • camtasia1000 4 years ago

    You are god…..

  • Flawless Cowboy 4 years ago

    I’m going to fail.

  • Victoria Hoang 4 years ago

    i like the way you explain it but it’s not really interesting, your tone of voice. this video helped me though.

  • Ihab Ayoub 4 years ago

    This here in Algeria a 9 grade student can solve that so easily

    • Dubidooba 4 years ago

      Ihab Ayoub too bad ur still in algeria

  • ekuhnle 4 years ago

    For the last problem, can’t the denominator also be written as x^2-4 > 0 ? Surely it can be divided by a number greater than 0.

  • masterofdizaster 4 years ago

    you look so tired and sad in this video, is everything alright? i still think its great despite your seemingly bad mood, and you helped me a lot!

  • Brandon Heald 4 years ago

    1.25 video speed recommended.

  • gvukster 4 years ago

    How do I find your domain?

  • salchu sangma 4 years ago

    Can you make a video on how to find absolute minima and maxima and local maxima and minima

  • edward moonga 4 years ago

    Thank Nancypi you have solve my puzzle

  • Jessica Delgado 4 years ago

    Your video really helped thank you

  • Aakash Jana 4 years ago

    NancyPi after watching your videos i started liking math !!

  • Andersen Boykin 4 years ago

    i love you

  • glister goodness 4 years ago

    So nice I love all your videos can you make videos on suites

  • Dr Bh 4 years ago

    Your amazing thank you

  • Shivam Tiwari 4 years ago

    Nice explanation with all sort of minors

  • Muhebullah Muheb 4 years ago

    I really like the way that you teach would you please make a video for Graph function I would really appreciate it Thank You

  • Ernest Nicholas 4 years ago

    Thank you so much God will bless you

  • Thilak malporu 4 years ago

    Thank u ….

  • Matakala Matakala 4 years ago

    I like the video but am not convinced with the function 2/x^2 + 3

  • Serah Sharon Peter 4 years ago

    Thanks Nancy

  • Gui af 4 years ago

    So we’re just going to ignore the fact that she’s writing backwards??

  • Saleh Aboutaama 4 years ago

    Among all courses and videos of how to get the domain of a function yours is the best and the most clear and accurate one. Only because you justified that functions are divided into 5 types (Polynomial, fractions…etc)

    I really do thank you very much for being clear and precise while explaining math 3>
    keep up the good work Nancy

  • Jonah Gustavson 4 years ago

    Thank you so much for posting these videos Nancy- they are very helpful, and you do a great job presenting them. I used to have a YouTube channel where I would present weekly in front of the camera. The nerves can take over as soon as the red light is on. Keep it up!!

  • Habiba bint islam 4 years ago

    Thank you 😊❤️❤️❤️

  • Fuzion Velez 4 years ago

    This literally saved me for my quiz tommorow

  • Chayito C. 4 years ago

    I like math and your videos.

  • John Doe 4 years ago

    How can anyone click thumb down? Please be decent, Nancy videos are fantastic if you want to learn. I’ve been watching her videos for years.

  • Jay O Smitty 4 years ago

    this is awesome…i have addded this to my playlist being that I have looked at it for 5 different problems

  • Contemplateboxing 4 years ago

    I appreciate this video..though, I thought I was following the steps just as in the video…but, still managed to bomb my homework questions…

  • Burak Kaklik 4 years ago

    bruh i couldnt even focus lmao

    • Astika Touchstone 3 years ago

      she is really pretty.

    • bruv 3 years ago


    • -Lord 3 years ago


    • Mariam Hagh 3 years ago

      you know your life is going downhill when you simp for a math teacher: bringer of pain.

    • Varsha 3 years ago

      @Mariam Hagh lmaooooo

  • T W 4 years ago

    Love your videos. Nicely done. Thank you!

  • Blind Truth INC. 4 years ago

    your videos helped me alot thanks nancy. I grew a crush on you as well

  • Ian Green 4 years ago

    Does she write everything in reverse?

  • Haris Saeed 4 years ago

    how to find the range

  • Carol Jackson 4 years ago

    Thank you Nancy. I have watched many videos and yours has really clarified solving for the domain.

  • Aso Wrath Ali 4 years ago

    I love your math help thx Nancy

  • prod. Yung Braidy 4 years ago

    hot math teacher actually makes me better

  • dea hosel 4 years ago

    Hi my name is dea, I was wondering how do you find the domain for exponential functions?

    • iasoe 3 years ago

      is it all real numbers?

  • KUSH KUMAR 4 years ago

    I love you jaan

  • prodby404 4 years ago

    do you write backwards or just flip the video ?

  • Basil Molewa 4 years ago

    Thanks for the help ,everything is broken down into consumable pieces thanks for doing such a wonderful wonderful job…Hope to learn even More as time goes on Thanks a load.

  • Jaap Ongeveer 4 years ago

    Awesome, thanks very much!

  • Issa Bitar 4 years ago

    she’s hot asf

  • Person Of Interest 4 years ago

    Holy crap is she writing everything backwards on the glass? That’s really impressive!

  • Top List 4 years ago

    Any one else use these videos to fall asleep?

  • Lee Ann 4 years ago

    You know what’s worst than studying math 😭😭studying math in chinese 😭😭

  • Emeka 4 years ago

    thank you. really needed this. keep doing what you’re doing!

  • Edmund Castellanos 4 years ago

    😍 you teach i love math hehe

  • tonty rutinel 4 years ago

    You are THEEE best

  • Y C 4 years ago

    I didn’t just like the video. I loved it. Thank you.

  • Discrete Affiliation 4 years ago

    Maybe its just my narccisism, but i feel like shes flirting with me

  • TrueVerdicts 4 years ago

    She doesn’t write it backwards. She inverts the video after shooting it.
    It’s that simple. Why are so many people baffled!

  • Abdulla Doha 4 years ago


  • almuhanad Alhashmi 4 years ago

    i like math

  • almuhanad Alhashmi 4 years ago

    Teacher in the example of sqr(x^2 + 5x + 6) you make mistake in writing the domain it must be x greater than or equal to 0 thank you

    • jesuisravi 4 years ago

      no. She’s right. It can’t be equal to zero.

    • The Predator 4 years ago


  • John Gumuan 4 years ago

    You are better than my math lecturer. God bless you. This is my best class room

  • Chandan Balu 4 years ago

    I love the math because of this woman!

  • NW3D 4 years ago

    The akward stare after the problems crack me up.

  • RubiMercuri 4 years ago

    Using this to review for my precalc 1 exam tomorrow wish me luck

    • Sam Stellar 4 years ago

      Hope you aced it

    • Diego Vera Acevedo 4 years ago


    • RubiMercuri 4 years ago

      I got a 91/100

    • phoebe rashid 3 years ago

      @RubiMercuri wow Rubi tell me the secret am really bad at math

  • Jerohm Villanueva 4 years ago

    love you

  • Rut Afim 4 years ago

    Love you and like your vidio but what about range

  • Becky Waibe 4 years ago

    thanks! I loooove you

  • Cooldibs 4 years ago

    I don’t think math has ever sounded so hot

  • Abhijeet marshall 4 years ago

    Wow amazing nancy
    Have fallen in love
    With your awesome tips

  • Sara Norton 4 years ago

    Thank you so much! This is the most straightforward and helpful video I have found on this topic.

  • Jody Marshall 4 years ago

    44 seconds in, and I already understand better then my teacher or text-book has been able to outline! Thank you so much!

  • Zakieldin 4 years ago

    Is the domain and “maximal domain” the same thing?

  • Mixa - ميخا 4 years ago

    For God’s sake people, she is not writing backward.
    She writes normally and then the video is flipped with some software.
    EZ, GG.

    • Devon Scoles 3 years ago

      why did you say EZ GG please stop

    • Eage 3 years ago

      @Devon Scoles maybe he is a toxic and a friendly guy xd

  • Bollywood News 4 years ago

    Hii you explain that pretty gud

  • Butt Shab 4 years ago

    U r hot

  • johnny makasalanan 4 years ago

    you look like cole sprouse

  • Ben Vredevelt 4 years ago

    Thank you Nancy!

  • Bia Renthlei 4 years ago

    You let me understand the basic MATHEMATICS that I can’t understand before thank youso much

  • relish ghimire 4 years ago

    I haven’t understand any thing

  • Ahmed 4 years ago

    Hottest maths teacher

  • Mylisa Kay 4 years ago

    Best video I have found on Youtube on Domain!

  • NICOLE CASTRO DIAZ 4 years ago

    Wait she is writing in mirror?????

  • NICOLE CASTRO DIAZ 4 years ago

    I don’t understand on the FRACTION ONLY why was the domain all real numbers. it can’t equal -3 but then it can’t equal -2 or -1 either? confusedddd

    • Grace T. Haokip 3 years ago

      NICOLE CASTRO DIAZ tht coz the variable was in terms of square and u cannot hv -ve inside the swamp root so we hv to assume that the domain is all Real nos

  • Laxman Kamat 4 years ago


  • joi s 4 years ago

    Hi Nancy… 👍

  • Pasha Maeh 4 years ago

    Thanks, like, sincerely. Damn this is so useful. This makes more sense than my class

  • cool cool men 4 years ago

    Can you do more better than that because i knew all these function . i think you have to add more function like log,ln,modulus

    • j jha 3 years ago

      If you have knowledge so plz solve x^2-x+1/x^2+x+1 range solve

  • Asim Jatt 4 years ago

    Can u solve this question domain and also range g(x) =|x_3|

  • Sarah Pendhari 4 years ago

    Can you please explain with pseudo quadratic as well

  • Sarah 4 years ago

    If she didn’t make her math videos, i would fail my math class. she’s a saint.

  • Kafee Al_Qahtani 4 years ago

    I like ya

  • Rooble Jama 4 years ago

    What about logarithm function and it’s domain

  • N. T. 4 years ago

    Fantastically organized and straight to the point video, thank you

  • DEIGO 4 years ago

    Is your hand okay?

  • Kh Bertlian 4 years ago

    Find the domain and range of f(X)=X|X|

  • Jeffrey JeffreyFLF 4 years ago

    Beauty helps me study. That is why I study using Nancy’s video.. And I don’t watch any other math video who a guy is teaching because Math guys teachers are assholes! and difficult to understand!!

  • Petrus Andreas 4 years ago

    Does the domain only focus on denominators???

  • Kumar Shaswat 4 years ago

    Maths has never been so beautiful 😍😍

  • Julia Lauren 4 years ago


  • serrano 0.l 3 years ago

    Thank you. Simple and made me actually pay attention. Kudos to you!!

  • DWang 3 years ago

    there’s a mistake, anyone noticed?

    • Ronnie Tactay 3 years ago

      Is it the greater than or equal to negative 2?

  • marymc333333 3 years ago

    Outstanding Nancy, thanks so much. -Mary

  • Leandro Botalon 3 years ago

    Why is it that all nancy are beautiful? nancypi, nancymcdoney, and nancy binay.

  • some guy 3 years ago

    Why are you so nervous

  • some guy 3 years ago

    I watched kahn academy 5 times and nothing helped this makes so much more sense thanks

    • Norcal 3 years ago

      Khan academy is hit or miss sometimes with their guides

  • James Pedid 3 years ago

    To find the domain of the function: look at the A in the symbol f : A -> B

  • Wlodimir Wladomir 3 years ago

    How do you write backwards?

  • Katelyn Valenzuela 3 years ago

    Thank you!!!!

  • Joshua Velazquez 3 years ago

    she’s too hot I cant focus…

  • J Valiente 3 years ago

    How to find range please ? huhu… best teacher in youtube <3

  • John Patrick Tulda 3 years ago

    You don’t have to like math … But you can like my video.

    Me: i like you

    • Abdulrahman N. 3 years ago


    • Pedro Hernandez 3 years ago

      @Abdulrahman N. Swamp

  • Rosa Delgadillo 3 years ago

    @5:03 why is the domain negative infinite to positive infinity, wouldn’t it be negative infinity to negative 3??NEED HELP UNDERSTANDING WHY ITS TO POSITIVE INFINITY

    • Yani Bueno 3 years ago

      there’s no x value that would ever make -3 happen when you square it. because when you square any negative or positive number it would always end up as a positive number. that’s why she said -3 would never be possible in that equation so you don’t need to worry about it or include it. that being said, any real numbers, negative and positive, can be a function of x in this equation. you can input any number and it would still generate as a function of x. that’s why she wrote (-infinity, infinity). hope that helps. 🙂

  • MasoniteShadow 3 years ago

    THANK YOU SO MUCH. nowhere else in any textbook or internet explained finding the domain as well as you have.

  • JASON AL RUBAIE 3 years ago

    You did a great. It’s so benefit to me.

  • Aaron Herrera 3 years ago

    Great video, thanks a lot, this really helped me with my functions!

  • Imora Perez 3 years ago

    Thank you so much!! I get it now lol

  • Achuei Aguer 3 years ago

    thanks for the video…really helped

  • SOURAV SIR 3 years ago

    Wow what a great video 😍.
    Everything in just small video superb🤗.

  • Alex Cruz 3 years ago

    daaaaaaaang she fine affff… dat voice tho geeez

  • SOURAV SIR 3 years ago

    How to find range make video on that also fast🏃⛷️

  • Omar Waleed 3 years ago

    Nancy your too attractive for me to actually learn anything from what your saying.

  • eym groot 3 years ago

    Thank you for making my life easier! Lol teachers really tend to make it complicated -_- smh. Btw i love your voice❤

  • Smoke Giver 3 years ago

    Can you do a video like this but on the range

  • Joseph Travelstead 3 years ago

    Give yourself a hug cause you rule!

  • HAFASHA ARTHUR 3 years ago

    hello, thank you for the service i would like you to help me with sketching the absolute values of functions

  • aceraven 3 years ago

    holy FUCK this girl is hot

  • Charl0z1 3 years ago

    I love when random people on YouTube are better teachers than people with >masters degrees. I bet it was great back in the day when teaching was a revered career.

  • Oliver Mon 3 years ago

    Your beauty disturbed me ;p

  • l Collins 3 years ago

    Thankkkkkk youuuuu

  • Zabi Amiri 3 years ago

    on of the best explanation ever and i just love you

  • J Curry 3 years ago

    When would I know to put a bracket or a parenthesis

    • ella kiel 3 years ago

      if it is solid or hollow

  • shagy yy 3 years ago


  • Sanjay Rathore hardoi gujar jaloun 3 years ago


  • paigey ok 3 years ago

    Just wanted to let you know that this was very helpful 🙂

  • lalit bahadur thapa 3 years ago


  • Oscar Orfiano 3 years ago

    She made a mistake in square root of X^2+5x+6 coz inequality flip in value of 3.

    • chelsea. 3 years ago

      yeah i’ve been looking for that comment. so, it could be “x greater than -3 and -2” , isnt it ?

  • FRANCIS MWANZIA 3 years ago

    the coolest finishing statement,dont have to like math….

  • David 3 years ago

    Her backwards handwriting is better than my handwriting at 1 wpm

  • kayla griffin 3 years ago

    I’ve had TWO different teachers explain this to me and nothing, I tried khan academy and nothing. But you is a blessing because I understand every. Single. Word.

  • Jose Sings 3 years ago

    Hi I’m gonna need help more Thank grateful for helping but need more help

  • Muhammad Ali Hamza 3 years ago

    very difficult to focus on question

  • sophiamarie101 3 years ago

    how r u writing backwards

  • Umer Ahmed 3 years ago

    You are sexy as fuck

  • Zainab 3 years ago

    Wow I have never enjoyed math this much. You are so calm

  • Ehsan Khokhar 3 years ago


  • Ehsan Khokhar 3 years ago

    also thanks for the description of video

  • Jose Luna 3 years ago

    Why is she kinda mad in this video?🤔

  • allsparkwars2 3 years ago

    Beautiful video and gorgeous face

  • Fatoumatta Trawally 3 years ago

    What if you have a root inside the root

  • Abbir Ali 3 years ago

    Excuse me ! May i go to Washroom 🖐🏻

  • Abbir Ali 3 years ago

    Maam are you writing on screen of the cam 😵🤦🏻‍♂️

    • A volatile noodle 3 years ago

      I hope no one needs to answer your question

  • Airborne Alice 3 years ago

    You are a great teacher ❤️ thanks for your effort

  • Ramirez_Vlogggss 3 years ago

    yo thanks for the explanation, I have finals this Friday this really gonna help me out

  • Alisha Majid 3 years ago

    You are a life saver❤️

  • Ella Rue :3 3 years ago

    Me: Yes. I am indeed. Because there are some really good teachers on youtube who deserve respect.

  • loren steele 3 years ago

    This video was a great help & now problems’ solved

  • Lindsay Cook 3 years ago

    You remind me of Violet from the Incredibles.

  • Alex K 3 years ago

    OMG Im so happy she made a video on this!

  • Rampart D. 3 years ago

    Thank you so much. God bless you

  • Sir Ivan Wide 3 years ago

    Be careful with the numbers included and not included accordingly apply the brackets

  • Asadian Belifont 3 years ago

    How the hell can a 10 minute video on Youtube literally be more educational than a 3 hour math class, taught by someone who has done it for years. We need to replace teachers with youtubers.

  • sebastian7494 3 years ago

    Please make a video on “how to find range of any function”. I absolutely need this!
    And thank you for the video! You are an excellent teacher.
    Liked, Subscribed!

    • Alexandra Sniezek 3 years ago

      I think all you have to do is find the domain of the function’s inverse, so if you know the inverse, than you can find the function’s range.

  • Yeakub Hossain 3 years ago

    Dear Mam, Tomorrow morning is my math exam (first term). I took my math teacher consultant hour also 3 extra class about domain and range but more than 60% student did not understand this term. after watching this video i totally understand how to find Domain. but i still do not understand how to find Range.
    Would you please make second video like this about How to Find the Range?

  • Mindly Wander 3 years ago

    Honestly, you are really saving my non-mathematical bottom part. Thank you! 😀

  • Dana Ali 3 years ago


  • ufooooooooooooooooo 3 years ago

    Barely noticed that if you write on anything transparent like her glass or plastic the reflection on a mirror or flipped video comes out the same because it’s the back side of the writing, pretty cool… and something about the domain of fractions I think?

  • Rebecca Glover 3 years ago

    Why couldn’t my teacher just explain it like this?! Thank you 🙂

  • Amanda Robinson 3 years ago

    Her videos were very useful for me and now I can help other people with their algebra

  • Christopher Taylor 3 years ago

    What about absolute value?

  • AJvanuw 3 years ago

    I searched for lie derivative—but this is much better

  • MarioDeSanta97 3 years ago

    You are absolutely gorgeous

  • - iOmidus 3 years ago

    Does this works for inverse function and composite function?HELPPP!

  • Sweet-Tish Eatz! 3 years ago

    Girl this does not help at all. You people come on here calling yourself helping but you aren’t be clear about how or why you are making the solutions. I need to know why you got the (-3) and so on.

  • mbs 07 3 years ago

    You didn’t have to have like maths but can like my video 😂👍🏿

  • mbs 07 3 years ago

    Make on range too plz

  • Candy 3 years ago

    why cant i still understand it!!! how my teachers explains are different from this.the examples they give is so damn hard. but the way she teaches makes it easy!!!! but i still cant understand it!! im so stupid.

    • Math Whisperer 3 years ago

      Candy, I don’t know you but I know you are not stupid. There are so many ways to explain topics in math. There is a way, and probably more than one, that will work for you. Hang in there and believe in yourself!

  • BuZZaRD D 3 years ago

    Good content

  • HASAN SALEEM 3 years ago

    Thankyou so much mam i dont know how to thank you, i didnt knew this topic and tuesday is my cbse exam , lots of thanks from india

  • Zombie Mechanic 3 years ago

    You dont have to like Math…but you can go on a Date with me and like it

  • Samindika Dalanindu 3 years ago

    Thank you very much. Your skill is amazing.

  • Alexis Kennard 3 years ago

    Hey Nancy! Can you do a video for logarithms?

  • Shrey Rana 3 years ago

    This was amazing. Way to go! Learnt in an better way to solve the domain

  • selma moongo 3 years ago

    You are the best, as a first year medical student this helped me more than my lecturer, its for 2018 but still useful in 2020. You are keeping me busy during this corona lockdown. May God bless you with more wisdom to share with us more.

  • sihong 3 years ago

    wait i have a question; for (x^2) + 3 can’t you use an imaginary number or nah?

  • juel kumar 3 years ago

    u r very s…….,.

  • Aaron Herrera 3 years ago

    Thanks for the video, it makes sense to me now.

  • The Prince 3 years ago

    Very beuatiful miss😊♥

  • MANASH BORO 3 years ago

    liked your teaching

  • sweetpea 3 years ago

    Gorgeous and intelligent at the same time. Absolute goals. Thank you so much for the video. I’ve been trying to learn for weeks lol

  • sumon chowdhury 3 years ago

    your hair are looking amazing

  • morgan tiere 3 years ago

    cant concentrate, shes too beautiful

  • John Christopher Gabihan 3 years ago

    You’re really beautifull ma’am. I always watch your video tuturial. It really helps me a lot 👍 thanks a lot 😊 much appreciated 👍

    -from philippines

  • DYNAMIC ADI 3 years ago

    Do anyone knows about srinivas ramanujan:the man who knows infinity

  • 10D VISWA.R VVK 3 years ago

    Thanks for helping me to get that one easier♥️

  • Erin Larsen 3 years ago

    I watched my 2hr lecture twice and didnt get it. I watched 1 minute of this and thought “wtf this is easy” THANK YOU SO MUCH

  • Denis Ikonomi 3 years ago

    This video is literally exactly what I needed.
    It’s simple yet detailed which I really appreciate.
    Only thing that’s missing is domain of exponentials but other than that it’s pretty much perfect

  • datta lokhande 3 years ago

    thanks mam

  • Balamurali Chandran 3 years ago

    Can you add videos on Linear Algebra – Eigen/ SVD/PCA etc

  • Anu 3 years ago

    at 5:07 Can’t it be x= phi because it is not possible to have x^2=-3 so thre muist be no solution to it then how could we write it Real (-infibity,infinity) ??? Pls clear my doubt?

  • twerkformemes 3 years ago


  • udit saxena 3 years ago

    Thank you so much teacher lots of love u made learning super easy pls help others like this with much higher contents in an easy way infact u should charge for a course online u deserve it absolutely brilliant work 💖😍🌷🌷

  • isha pundir 3 years ago

    Why can’t there be a value for the square root of 3 , don’t we get a value in decimals ??

  • Tim Rubin Halcomb 3 years ago

    You’re very pretty.

  • vitthaldas jaju 3 years ago

    What if both numerator and denominator has square root?

  • Maneekiran Bali 3 years ago

    please explain logarithmic function , and for question i would suggest suggest to mix radical function at bottom and you can mix trigonometric functions for fun , that would be great and please give a complementary question on napier’s constant which should not be easy to solve, and do suggest to find range of them , and please make videos on these topic as soon as possible

  • 3xw _55 3 years ago

    Thank you very much ❤❤

  • me as myself 3 years ago

    hey😉u got new indian subscriber

  • Robert Lee 3 years ago

    best video I’ve encountered so far on explaining finding domain…thank you

  • Mathews Nachibanga 3 years ago

    Nancy your the best 🙌

  • Ved Tiwari 3 years ago

    Enough information u can get here
    Interesting method of teaching thanks

    • Ved Tiwari 3 years ago


  • Munna SINGH 3 years ago

    Nice teaching

  • Oromo Dance and Music Recording 3 years ago

    on 7:52 the sign of less or equal is not right

  • Esther Oh 3 years ago

    i have a question idk if you’ll see this but for the “square root only” the 2nd example,, how do you know when to switch the inequality signs…. i was just confused about that BUT THANK YOUUU

    • Boluwatife Adekoya 3 years ago

      When solving an inequality with a quadratic equation like that that will give you two values, you have about 4 ranges, say, x greater than-2 and, x less than -2 and same for -3
      Try and draw all four on a chart and see which two will give a wider range

  • Vivek Yadav 3 years ago

    Not gonna lie, I already knew the concept… 😉

Comments are closed.