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Power rule introduction (old) | Taking derivatives | Differential Calculus | Khan Academy

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  • เผยแพร่เมื่อ 2 ต.ค. 2007
  • Determining the derivatives of simple polynomials.
    Watch the next lesson: www.khanacadem...
    Missed the previous lesson?
    www.khanacadem...
    Differential calculus on Khan Academy: Limit introduction, squeeze theorem, and epsilon-delta definition of limits.
    About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content.
    For free. For everyone. Forever. #YouCanLearnAnything
    Subscribe to KhanAcademy’s Differential Calculus channel:
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ความคิดเห็น • 317

  • @54321conor
    @54321conor 8 ปีที่แล้ว +519

    It's been 8 years and almost 10 months since this video was made... I sincerely hope he's gotten a new pen by now.

    • @MoreParksLessParking
      @MoreParksLessParking 8 ปีที่แล้ว +41

      He already did. Give it another 8 years and you'll probably be watching Khan Academy in 3D.

    • @bananabananae
      @bananabananae 8 ปีที่แล้ว +2

      +The Family Picture lol

    • @MoreParksLessParking
      @MoreParksLessParking 8 ปีที่แล้ว +6

      ***** You just wait. You'll feel like you can just reach out and touch the polynomials with your fingertip!

    • @engelshentenawy
      @engelshentenawy 7 ปีที่แล้ว +1

      lol that's good !

    • @vtron9832
      @vtron9832 7 ปีที่แล้ว +3

      He already got a new pen and everything looks clearer now, I try to avoid his videos with the old pen and try to look for another one about that same topic

  • @remluf123
    @remluf123 11 ปีที่แล้ว +114

    Whenever I watch Khanacademy's videos, I feel like the entire universe just makes total sense all of a sudden.

    • @dularar8934
      @dularar8934 3 ปีที่แล้ว +3

      How is it going 8 years later

    • @78anurag
      @78anurag 3 ปีที่แล้ว +2

      @@dularar8934 If she was learning this in high school as a freshman (where most people do) she probably has graduated with a master's degree.

    • @hoganmarhoefer5390
      @hoganmarhoefer5390 2 ปีที่แล้ว +5

      @@78anurag freshman in hs taking calculus i or AB, no way.

    • @Wallyisking
      @Wallyisking ปีที่แล้ว

      This is one of the best things to come from the internet (imho) - an altruistic push towards free, quality education available to anyone. Not only that, but the teaching methodology improves over time, so the learnability and retention of material can improve for students of all backgrounds! Loved Sal's TEDTalk on AI and Education, he's a true pioneer.

  • @StanBobPoe
    @StanBobPoe 8 ปีที่แล้ว +40

    Better than any textbook and probably most professors that try and teach this subject. Thank you for all that you do!

    • @BhavyaHemnani
      @BhavyaHemnani 7 หลายเดือนก่อน

      You needed better textbooks man, try RD dharma Class 11 or HC verma vol 1

  • @Baconthief1
    @Baconthief1 9 ปีที่แล้ว +82

    Learned more from this than my entire semester so far.
    Mrraaaaggghhh!

    • @discuss2130
      @discuss2130 9 ปีที่แล้ว

      Very worrying if this is true. What on earth goes on where you are studying, do you or any teachers do any work there?

    • @Baconthief1
      @Baconthief1 9 ปีที่แล้ว +2

      It was a russian who could not be understood. I was exaggerating also

    • @Baconthief1
      @Baconthief1 8 ปีที่แล้ว

      Cal is easy, it's all good. (One year later)

    • @omarkhattab2402
      @omarkhattab2402 6 ปีที่แล้ว

      Merica how about now

  • @redangrybird7564
    @redangrybird7564 5 ปีที่แล้ว +31

    God bless the guy who invented the internet. 😆
    Here I am in the middle of the Australian bush learning calculus.

  • @ICT_Gem
    @ICT_Gem 3 ปีที่แล้ว +5

    This is one of the best channels on TH-cam and I feel so sorry for fellow students who haven't come across it yet. You've made me fall in love with calculus. Thank you

  • @rgbok5453
    @rgbok5453 4 ปีที่แล้ว +19

    Someone buy this helpful man a bamboo drawing board so he can write in peace.

  • @Tomwenn
    @Tomwenn 14 ปีที่แล้ว +4

    My teacher looks useless next to this, I would like to thank you for saving my university place for September...I was about to fail calculus. I could not understand a thing, until now.
    Thanks so much!

  • @chad3193
    @chad3193 10 ปีที่แล้ว +11

    This semester was my hardest math class I'd felt in my life, but after I watched this video!!! You're awesome Salman, You helped me a lot.

  • @fabse64
    @fabse64 12 ปีที่แล้ว +1

    You sound so happy throughout all of these videos.
    Listening to you talking sounds like, "And let's say :D :D x is equal to :D :D :D 4 and :D ..."

  • @xSabretoothx15
    @xSabretoothx15 11 ปีที่แล้ว +9

    Not sure why everyone's guffawing over the "I'm 15 years old" comment. It's not hard to watch a video on TH-cam when you're 15. As long as you're not intimidated by the idea of calculus, learning it from Khanacademy isn't any harder than learning arithmetic when you were little. The fear is what kills most people.

    • @cosmics999
      @cosmics999 4 ปีที่แล้ว +1

      but im 9 years. old

  • @Xasperato
    @Xasperato 8 ปีที่แล้ว +74

    Never thought I'd think this, but calculus is fun. (*_*).

  • @dannybaker7366
    @dannybaker7366 3 ปีที่แล้ว +2

    This man is a legend he is saving me from failing my calc quiz 12 years later :)

  • @shinNn877
    @shinNn877 8 ปีที่แล้ว +9

    Thank you so much for helping me in conceptualising things. You do save me a lot of time. Thanks!!

  • @theonetrueac
    @theonetrueac 12 ปีที่แล้ว +1

    I also want to once again thank Sal, and all the people that make these videos possible. Most of us realize he was the driving force, but other people have contributed aswell. These videos helped me through my precalc course to end with a high B after coming in way behind not knowing alot about algebra. They are now helping me learn physics and the calculus behind the calculations for the equations. Thanks again guys/girls, and special thanks to you sal, for being such a great teacher.

  • @ollie8500
    @ollie8500 7 ปีที่แล้ว +5

    This makes so much more sense than what my teacher taught me 🙏🏼

  • @Gimipork
    @Gimipork 16 ปีที่แล้ว +1

    Sal, you're a genius. Why can't everyone explain as well as you do? Whenever I'm stuck in my mathbook, I look at your vids and it's just crystal clear. Thank you :)

  • @Alternate555
    @Alternate555 14 ปีที่แล้ว +2

    I'm just trying to learn ahead, but I gotta say this: You are amazing. Keep up the good work.

  • @FirefoxMancer
    @FirefoxMancer 13 ปีที่แล้ว +1

    So many comments of thanks, but I feel the need to add mine as well.
    Many thanks for taking your time to spread free education, especially on such a vast scale. It is truly a marking point in the evolution of man when learning becomes viral. It truly marks a point in the evolution of man, as we approach perfection. What an honor Mr Khan.

  • @kylemarrotte8595
    @kylemarrotte8595 10 ปีที่แล้ว +77

    He never gets a new pen tool, does he?

    • @discuss2130
      @discuss2130 9 ปีที่แล้ว

      Something seriously wrong with his computer and software. He needs to get it sorted before recording any more videos. It is like a broken record, oh my pen stopped working again, blah blah,,,, come on now, you've got an MS in Engineering after all. What a joke!

    • @rlrfproductions
      @rlrfproductions 9 ปีที่แล้ว +7

      discuss21
      You really don't know who he has become since,eh? Check out khanacademy.com

    • @xDCrossFireSure
      @xDCrossFireSure 9 ปีที่แล้ว +2

      Kyle Marrotte It was uploaded in 2007.

    • @Peter_1986
      @Peter_1986 6 ปีที่แล้ว

      +discuss21
      Just because he has a degree in Engineering it doesn't mean that he wants to stop the video and fix his pen tool.
      Also, he might hope that it will eventually stop malfunctioning.

  • @nohackers2037
    @nohackers2037 4 ปีที่แล้ว +1

    In my class we did the same thing but my teacher explained it different. He never explained why
    He said " We have 4x^5 multiply by the power (5)(4x^5) and reduce power by one (5)(4x^5-1) which is 20x^4"
    You explain it as "4x^5 = 4 (dy÷dx x^5) = 4 (5x^4) = 20x^4"
    Your way is so much easier to understand!

  • @Cdoddsy
    @Cdoddsy 14 ปีที่แล้ว

    ...my teacher just needs to keep his mouth shut and show these videos during class..., the man whispers and talks fast....which is why I have to learn from youtube, these videos are a life saver

  • @PhilipMalm
    @PhilipMalm 12 ปีที่แล้ว

    Got my IB Math exam tmr... ive been going through almost all calculus videos now. Ive learned more from this guy on a few hours than 1 year of my teachers teaching..

  • @schneebly4life
    @schneebly4life 14 ปีที่แล้ว

    Screw paying a tutor when there are so many better ones online for free...and most of them make perfect sense and more than my teachers! Thanx for the videos

  • @Ronnie7X
    @Ronnie7X 10 ปีที่แล้ว +14

    Students : 1
    Guy calling on the cell phone : 0

  • @DaReaperZ
    @DaReaperZ 13 ปีที่แล้ว

    This guy should be everyone's teacher, because the learning is supreme to any other :D
    Even for me who doesnt have english as a main language!

  • @nikethagiri4249
    @nikethagiri4249 5 ปีที่แล้ว +9

    "This pen drives me nuts..."

  • @mariejanepoirier779
    @mariejanepoirier779 5 ปีที่แล้ว

    I am SO HAPPY that you help me every day understand math concepts that my proffessor tries to explain... I would fail my semester without your videos.

  • @milindthegreat
    @milindthegreat 12 ปีที่แล้ว

    dude u rock man keep up the gud work u really doing something dat is very moral. i m in school n i m gonna a give a IIT(really tough all india engineering exam) for which my tutions r charging about half a million Rs so wat u r doin is really helping a lot of ppl who r not dat privileged keep it up

  • @phenomenalphysics3548
    @phenomenalphysics3548 5 ปีที่แล้ว +3

    Thank you, thank you, thank you so much, your videos had been such a great help! Thank you!!!❤️❤️❤️

  • @shreyagupta130
    @shreyagupta130 2 ปีที่แล้ว +1

    Now, whenever I'll study Derivatives I'll think about the malfunctioning pen which drove Sal crazy

  • @93stormer
    @93stormer 13 ปีที่แล้ว

    Greatest teaching quote ever: "the more examples we do, the better."

  • @Emma16182
    @Emma16182 11 ปีที่แล้ว

    Math is FINALLY starting to make some sense!

  • @ilovesomaligirls
    @ilovesomaligirls 13 ปีที่แล้ว

    I was bewildered and feared I might fail my Applied Calculus class but since I found your excellent tutorial videos, I am confident I can beat and be one of the 5 scoring students in the class!! And indeed, I wholeheartedly thank you Salman. May Allah bless you with Janatul Fardowsa*

  • @chestypants78
    @chestypants78 11 ปีที่แล้ว

    Most helpful, enthusiastic and optimistic teacher I've seen. I 'Like' Sal's videos at the beginning. There's a 100% chance that the video will be helpful. :)

  • @rajottam
    @rajottam 11 ปีที่แล้ว

    salman, this is gr8... I wish we had better teachers in school..I had to rote learn all the formulae..

  • @larendaren
    @larendaren 14 ปีที่แล้ว

    this is way better than my teacher, wow....cant thank you enough

  • @JoshNM24
    @JoshNM24 13 ปีที่แล้ว

    you're sooo much better than my teacher! i didn't know what i was doing until i watched your videos! muchos gracias!!

  • @SirFickDace
    @SirFickDace 13 ปีที่แล้ว

    Thumbs up for this guy helping us in college!

  • @kevinzhu9226
    @kevinzhu9226 11 ปีที่แล้ว

    you are a lifesaver! I wish all teachers were capable of teaching like this

  • @kirankulkarnikirankulkarni
    @kirankulkarnikirankulkarni 5 ปีที่แล้ว

    Feels so great to unlearn and relearn calculus now after so long (may be 14yrs) :D

  • @nustylez
    @nustylez 13 ปีที่แล้ว

    you calculus videos helped me gain a better understanding of the topic. i seriously can't thank you enough for what you are doing for those such as myself who need help.

  • @dildar1446
    @dildar1446 12 ปีที่แล้ว +1

    U DESERVE THE NOBLE PRIZE MORE THAN MR OBAMA. I MEAN LOOK AT THIS GUY HE IS TEACHING SOMEONE IN AMERICA, ME IN MIDDLE EAST AND GOD KNOWS WHERE IS THE OTHER ONE. I JUST WANT TO SAY A BIG THANK YOU

  • @ftit5893
    @ftit5893 4 ปีที่แล้ว +2

    omg u made derivatives fun

  • @SHADOWSTRIKE1
    @SHADOWSTRIKE1 13 ปีที่แล้ว

    Thank you so much... I have a terrible time in school... between ADD, and just a simple lack of desire to learn, I rarely walk away from a course learning anything. However, out of the 30 minute's I've spent watching your videos, I've learned more than this entire semester of college.

  • @georgeredacted4682
    @georgeredacted4682 11 ปีที่แล้ว

    Wow, watching these videos made calculus sound 100 times easier. Thanks.

  • @atn_holdings
    @atn_holdings 12 ปีที่แล้ว

    That's the point of the derivation: we are searching the slope of a curse at a specific point, which will be equal to the slope of the *tangent* of the curve at that point.
    A tangent is a straight line that touches a curve at one and only one point; if you put a (perfect) ball on a table, you can say that the table is tangent to the ball. Calculating the derivative is like putting a ruler on curve and detmining that the slope of the curve at the point of contact = slope of the ruler.
    Cool?

  • @Aaron-hg8jo
    @Aaron-hg8jo 3 ปีที่แล้ว

    oh my gosh this video was uploaded when I was supposed to be learning this in high school. Now I'm learning it and I'm 30 trying to get back into college

  • @blkstarr826
    @blkstarr826 14 ปีที่แล้ว +1

    omg! thank you thank you thank you! finally...someone just being plain about it! geez!

  • @130ipower
    @130ipower 15 ปีที่แล้ว

    dude ur pretty good i like ur style and teaching method. pretty awesome im understanding this better. im from sydney australia and pretty impressed with your work. this is helping me get me into shape for me to understand some complex economic theories.

  • @ElisavanYaslana
    @ElisavanYaslana 12 ปีที่แล้ว

    fighting a massive headache and studying for calc exam tomorrow, these are coming in massively handy. (Thank you) ^ ∞

  • @myearsburn2808
    @myearsburn2808 ปีที่แล้ว

    Let's be honest. Raising funds at tutors like Khan Academy and Organic Chemistry Tutor are more helpful to us than buying textbooks at this point.

  • @GreatProphet03
    @GreatProphet03 14 ปีที่แล้ว

    @WarmBread123 ..basically means 'differentiate with respect to x' (since you're only dealing with x then it's just telling you to take the derivative).... soon you might see dy/dx..and that's 'differentiate y with respect to x'

  • @jingjing23guy
    @jingjing23guy 11 ปีที่แล้ว

    This guy is easier to understand than reading "The Manga Guide to Calculus".

  • @shallowmartian
    @shallowmartian ปีที่แล้ว +1

    Somebody get this honorable man a good pen

    • @ddomainessrsls601
      @ddomainessrsls601 ปีที่แล้ว +1

      im sure that he has one now that it has been 15 years lol

  • @disney6858
    @disney6858 11 ปีที่แล้ว

    OH MY GOD!!!! THIS HAS BEEN LIKE A WEEK LONG SUMMER PROJECT!!!
    ALL I WANTED TO DO WAS KNOW HOW PPL FIRST CALCULATED PI AND NOW I'M ADDICTED TO KRACKACADEMY!!!
    help me :O

  • @Quercuspalustris50
    @Quercuspalustris50 12 ปีที่แล้ว

    I like the dy/dx notation because it really means 'change in y divided by change in x', so in a real world problem, when you know the change in x, you can then find the change in y (or visa versa); in other words if you're given a change in x, you can calculate the change in y, just by taking the derivative of the function and multiplying it by the change in x (algebraically). Am i making sense? Great videos, Sal! You're awesome!

  • @09AZ311
    @09AZ311 13 ปีที่แล้ว

    thank u , u are such an inspirational teacher, now because of you i found out that this stuff is easyyyyyyy, thx :)))

  • @cocaplayz1107
    @cocaplayz1107 10 หลายเดือนก่อน

    its been 15 years since this video was made, I don't know what ill do if he still hasn't gotten a new pen

  • @soloohk
    @soloohk 14 ปีที่แล้ว

    Its crucial to master the arithmetics of derivatives.
    Thank so much for bringing us this great tutorial !

  • @chaos.n.cosmos
    @chaos.n.cosmos 2 ปีที่แล้ว +1

    I guess, 14 years ago it was a big deal to even have the technology to manually write on a device.

  • @gwzombie9504
    @gwzombie9504 5 ปีที่แล้ว +1

    Nice video which help me a lot.

  • @alunatic4989
    @alunatic4989 2 ปีที่แล้ว

    I just spent 2h learning derivatives from scratch and the next video in my recommended is "10 signs you might have adhd". Feeling a bit called out rn.

  • @MrSamuelini1995
    @MrSamuelini1995 12 ปีที่แล้ว

    Thanks man I Skipped my homework to watch your videos

  • @TheMixedKid25
    @TheMixedKid25 15 ปีที่แล้ว

    he has more videos that can give you real practice.

  • @lompocus
    @lompocus 14 ปีที่แล้ว

    Very helpful for self-studying calculus! I'll cover the stuff in spivak and in another textbook I found for a dollar, go over problems in each, and refer to these videos to round out that comprehensive study! Thanks!

  • @UberCuba
    @UberCuba 14 ปีที่แล้ว

    @TiredNReclasMusic
    no the derivitave of 5x would be 5 because 5x^1 so 1 * 5 = 5 so thats the new co-effecient, and the exponent would be suptracted to it would be to the power 0 but thats only to the x. so it would be 5* x^0 = 5*1 = 5.

  • @95Homemade
    @95Homemade 12 ปีที่แล้ว

    im in grade 12 and this will help me alot this year. Thankyou very much!!!

  • @eliteXranger
    @eliteXranger 11 ปีที่แล้ว

    x^3 = 3x^2 because you do the power times the constant so 3*x = 3x and then the power you just used which is 3 us decriment it by -1 so 3-1=2 then 2 becomes the new power so final answer is 3x^2

  • @sumankanwar2255
    @sumankanwar2255 3 ปีที่แล้ว +2

    Who is watching this in 2021 and wanna prepare for jee

  • @femtecent
    @femtecent 13 ปีที่แล้ว

    the main point is, you learn something better than school.
    no matter what is behind this.

  • @MikeChung
    @MikeChung 12 ปีที่แล้ว

    Only if I could have you as my professor. My day will be a lot more easier and less stressful!

  • @tacos830
    @tacos830 12 ปีที่แล้ว

    Okay so known that as H approaches zero it equals f(x)+h-x (squared) divided by h. So then (x+h)(squared)-x (squared) divided by h= The limit as H approches zero which equals 0. So next if you take all that info you can see that is x (squared) +2xh+h (squared) -x (squared) divided by h so simplified it would be (2x+h)= 2x which is the formula for f'(x)=2x :)

  • @x3smil3zz
    @x3smil3zz 14 ปีที่แล้ว +1

    you're amazing! thank you so much for all you do!

  • @milesbennet
    @milesbennet 13 ปีที่แล้ว

    Incredible... Smile all over my face!

  • @OJYout
    @OJYout 11 ปีที่แล้ว

    Not necessarily, calculus doesn't come into the curriculum here in the UK at all until AS-level in 6th form. (age ~16-18)

  • @onurkarakus7538
    @onurkarakus7538 4 ปีที่แล้ว +1

    Simply fantastic, thank you

  • @KingAdam252
    @KingAdam252 15 ปีที่แล้ว

    very good absolutely useful too bad i couldnt find this three weeks ago lol hopefully you have something on partial derivatives thats what we are on now in class

  • @talatdhk
    @talatdhk 3 ปีที่แล้ว

    Derivative of constant can be simply explained like CONSTANT=CONSTANT*X^0=0*X^-1=0...

  • @BryTheNiceGuy
    @BryTheNiceGuy 13 ปีที่แล้ว

    Sal, you are a beast. :) I am planning on majoring in math and i was wondering what are some of the hardest math courses in college? Congrats for everything you do. Note: if i were a billionaire, i'd donate millions of millions to your academy and you since you quit your job in 09 :)

  • @CribBoy9
    @CribBoy9 11 ปีที่แล้ว

    easy way to know the derivative of simple functions like that are: n X ^n-1 where "n" is the variable of X

  • @S4disticJ0k3r
    @S4disticJ0k3r 12 ปีที่แล้ว

    I know how to do all the mathematics I just wanted to understand what it means in the real world. fyi you don't have to use the chain rule to solve that problem(if its even applicable) you can just take the derivative of the derivative. Chain rule is use in problems like cos(x^2) where you have multiple components at work.

  • @yuriythebest
    @yuriythebest 16 ปีที่แล้ว

    same thing here- I actually got a natural high and a good mood for the entire day, since I remember seeing all of this "matrix text" in class and here I'm all like "I know kung fu!"

  • @payasitopimpim2002
    @payasitopimpim2002 16 ปีที่แล้ว

    awesome my friend...all of us....really enjoy your videos...from lima peru

  • @atn_holdings
    @atn_holdings 12 ปีที่แล้ว

    The chain rule video explains what to do in that case.
    Namely, if f(x) = x^3/3, f'(x) = 3x^2 / 3 so x^2
    Not sure, though, I just watched the video, I never practiced the thing.

  • @crinclespandecoco
    @crinclespandecoco 12 ปีที่แล้ว

    It's more efficient to watch this 10 minute video rather than listening to my math teacher for 60 minutes a day..

  • @WhizzKidHouseMusic
    @WhizzKidHouseMusic 11 ปีที่แล้ว

    You can find a derivative by multiplying the coefficient by the exponent, then subtracting 1 from the exponent. For example, 6x^4 would be 24x^3. Idk if that helps anyone.

  • @DellorWeekly
    @DellorWeekly 15 ปีที่แล้ว

    classes aren't going to let you use that polynomial derivative shortcut.. was hoping i could get real prac! :)

  • @Phosphoer
    @Phosphoer 16 ปีที่แล้ว

    You are a skilled teacher! This has made my class much more understandable, I prefer you to my professor :p

  • @knm09c
    @knm09c 13 ปีที่แล้ว

    These videos are AMAZING! Khan Academy is a blessing!

  • @griff5274
    @griff5274 3 ปีที่แล้ว +1

    he makes this fun.

  • @dual85
    @dual85 15 ปีที่แล้ว

    This is the best academy ever! Ever!

  • @gowrishankarkn1465
    @gowrishankarkn1465 4 ปีที่แล้ว

    tysm man saving lives.

  • @PrankSmith
    @PrankSmith 10 ปีที่แล้ว +3

    I love you for this video

  • @BabyEnginee0
    @BabyEnginee0 หลายเดือนก่อน

    It's 16 year now. 🎉🎉🎉

  • @93stormer
    @93stormer 13 ปีที่แล้ว

    @iamtheplauge That happens a lot in my class. At least with computers and online videos you can go back and correct mistakes...

  • @ObiWanShinobi1
    @ObiWanShinobi1 13 ปีที่แล้ว

    I'm studying slightly ahead, because your videos are so fluid. thank you.

  • @edbbob
    @edbbob 13 ปีที่แล้ว

    Thanks for the excellent teaching. These videos are crystal clear, and very easy to understand.

  • @nutella871
    @nutella871 14 ปีที่แล้ว

    screw reading my textbook. i'll just watch these videos. much thanks :)

  • @S4disticJ0k3r
    @S4disticJ0k3r 12 ปีที่แล้ว

    From my understanding you said that the derivative is the slope of a point in a function on a graph is equal to the slope of a tangent line that passes through that point. What if your dealing with a function where the derivative is x^2. How can that be the slope if its not a straight line? I'm sorry if this doesn't make much sense I'm very confused.