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Відео

Meet the 94-year-old calculus teacher! @ycmathematicsphysicsandche5659
Переглядів 19 тис.День тому
Thanks to the UA-cam algorithm, I discovered Mr. Feng, a 94-year-old calculus teacher, @ycmathematicsphysicsandche5659 . He said in his note that teaching makes him happy and makes his life meaningful, which I resonate with so much. I want to make a video to introduce him to you! Please consider subscribing to his channel and supporting what he does. Thank you. The solution to the derivative ch...
First time solving an A-Level maths exam! (90 minutes, uncut)
Переглядів 117 тис.21 день тому
I will be doing a British A-Level further maths paper on the spot for the first time! This paper contains mainly algebra and calculus. Topics include complex numbers, hyperbolic equations, exponential equations, trigonometric identities and equations, first-order linear differential equations, determinant and the inverse of a 3x3 matrix, and more! Was I able to solve all the questions within 90...
The notorious three-circle problem from the GCSE
Переглядів 71 тис.21 день тому
Get started with a 30-day free trial on Brilliant: 👉brilliant.org/blackpenredpen/ ( 20% off with this link!) Here's the last question from the 2022 GCSE maths paper that made the news. We have three circles as shown and each radius is 4 cm. We have to find the area of the shaded region in the middle. I made a horrible mistake last time when I said the area of a circular sector is r*theta. The c...
Solutions to the 2023 AP Calc AB FRQ
Переглядів 31 тис.Місяць тому
Get started with a 30-day free trial on Brilliant: 👉brilliant.org/blackpenredpen/ ( 20% off with this link!) We will go over ALL the free response questions from the 2023 AP Calculus AB test to help you prepare for the upcoming AP exam. Topics included defined integral, average value of a function on an interval, change in position vs total distance traveled, implicit differentiation, related r...
You see nonlinear equations, they see linear algebra! (Harvard-MIT math tournament)
Переглядів 129 тис.Місяць тому
Get started with a 30-day free trial on Brilliant: 👉brilliant.org/blackpenredpen/ ( 20% off with this link!) This system of nonlinear equations is from the general round of the 2023 Harvard-MIT math tournament. www.hmmt.org/www/archive/271 I will present the linear algebra method I learned from their official solution to solve this system because I thought it was fascinating. It's from Harvard ...
Which is the worst math debate: 0^0, sqrt(1), 0.999...=1, or 12/3(4)?
Переглядів 243 тис.2 місяці тому
These are the most debated math topics on the Internet but which one is the worst? (A) 0 to the 0th power=1 or undefined. No calculus limit here. (B) sqrt(1) = 1 or both -1?) (C) 0.999...=1 or not? (D) order of operations 12/3(4)=1 or 16 More than 28,000 viewers voted in my recent poll and now let's discuss what each debate is all about. 🛍 Shop my math t-shirt & hoodies: amzn.to/3qBeuw6 💪 Get m...
You wouldn’t expect this "quadratic" equation to have 6 solutions!
Переглядів 116 тис.2 місяці тому
Surprisingly, the "quadratic" equation x^2 5abs(x)-6=0 has a total of 6 solutions (2 real and 4 complex solutions) which I did not expect. I came up with this equation purely by accident and I think it is super cool. It will feature complex numbers! 🛍 Shop my math t-shirt & hoodies: amzn.to/3qBeuw6 💪 Get my math notes by becoming a patron: www.patreon.com/blackpenredpen #blackpenredpen #math #c...
Using a logarithm property to make this equation easier!
Переглядів 87 тис.2 місяці тому
Get started with a 30-day free trial on Brilliant: 👉brilliant.org/blackpenredpen/ ( 20% off with this link!) We will solve this power equation x^ln(4) x^ln(10)=x^ln(25). However, the process of solving this equation would require making one side equal to 0 but factoring every term by x^ln(4), and I don't think the expressions will look that nice. So instead, we can use the log property that a^l...
My first calculus 3 limit on YouTube
Переглядів 88 тис.3 місяці тому
Get started with a 30-day free trial on Brilliant: 👉brilliant.org/blackpenredpen/ ( 20% off with this link!) This is my first video on a multi-variable limit that you will see in your Calculus 3 class. We will evaluate the limit of y/x as (x,y) goes to (0,0) but how do we take care of this? We do get 0/0 indeterminate form but can we use L'Hopital's rule? 0:00 Limit of y/x as (x,y) goes to (0,0...
Believe in geometry, not squaring both sides!
Переглядів 254 тис.4 місяці тому
Get started with a 30-day free trial on Brilliant: 👉brilliant.org/blackpenredpen/ ( 20% off with this link!) We will solve the equation that has two square roots sqrt(16-x^2) sqrt(9-x^2)=5 with a cool geometric triangle trick. In the end, we will also see if ChatGPT can solve this equation by using geometry. Check out a similar video on the proof of the Pythagorean Theorem and its inverse: ua-c...
Solution of the transcendental equation a^x+bx+c=0
Переглядів 149 тис.5 місяців тому
Learn contest math on Brilliant: 👉brilliant.org/blackpenredpen/ (now with a 30-day free trial plus 20% off with this link!) Today we will find a general solution to the transcendental equation a^x bx c=0. Here's an example 2^x-3x-1=0 ua-cam.com/video/GJbzsmccFtw/v-deo.html Check out a detailed the Lambert W function introduction: ua-cam.com/video/Qb7JITsbyKs/v-deo.htmlsi=bKnZW_lqlDjiKQuf 0:00 s...
My failed attempts to the integral of sqrt(sin^2(x))
Переглядів 108 тис.5 місяців тому
I have been trying to integrate sqrt(sin^2(x)) and get the same answer as on WolframAlpha, which is -sqrt(sin^2(x))*cot(x) C, but I just can't. So let me show you what I have tried (including how to integrate sqrt(x^2) with integration by parts) and maybe some of you will have an idea! 🛍 Shop Ultimate calc 2 integral sweatshirt: www.amazon.com/dp/B0C9L798F2 💪 Support the channel and get feature...
if x+y=8, find the max of x^y
Переглядів 674 тис.5 місяців тому
If x y=8 for nonnegative x and y, then find the maximum value of x^y. This question seems like a typical calculus optimization problem, but to find the exact answer, we will need to use the Lambert W function. ua-cam.com/video/Qb7JITsbyKs/v-deo.htmlsi=lc0IZ6aTrvewRBIh Check out my 100 calculus 2 problems to help you with your calc 2 final: ua-cam.com/video/Kwyk_mteyNc/v-deo.htmlsi=Dj_3rv2qeen7S...
Calculus teacher vs L'Hopital's rule students
Переглядів 83 тис.5 місяців тому
If you are also a calculus teacher, then you know most students will just use L'Hospital's rule for every limit after they learn the rule. So let's investigate the limit as x goes to infinity of (the integral from 0 to x of sin(t)*e^cos(t))/x and see why we cannot use L'Hôpital's rule. This is a great challenging limit problem for your calculus students! #calculus #blackpenredpen #challenge Rel...
combining rational exponents, but using calculus,
Переглядів 95 тис.5 місяців тому
combining rational exponents, but using calculus,
easy derivative but it took me 32 minutes
Переглядів 176 тис.6 місяців тому
easy derivative but it took me 32 minutes
My all-in-one calculus problem
Переглядів 94 тис.6 місяців тому
My all-in-one calculus problem
solving x^x=1 but x is not real!
Переглядів 117 тис.6 місяців тому
solving x^x=1 but x is not real!
the sine triangle problem
Переглядів 84 тис.6 місяців тому
the sine triangle problem
I couldn't solve x^x^x=2, so I solved x^x^(x+1)=2 instead
Переглядів 124 тис.6 місяців тому
I couldn't solve x^x^x=2, so I solved x^x^(x 1)=2 instead
Beyond the Gaussian integral
Переглядів 38 тис.6 місяців тому
Beyond the Gaussian integral
all solutions to 2^x-3x-1=0 (transcendental equation)
Переглядів 140 тис.6 місяців тому
all solutions to 2^x-3x-1=0 (transcendental equation)
finally 0^0 approaches 0 after 6 years!
Переглядів 451 тис.7 місяців тому
finally 0^0 approaches 0 after 6 years!
I want all trig functions in one integral!
Переглядів 618 тис.7 місяців тому
I want all trig functions in one integral!
Berkeley Math Tournament calculus tiebreaker
Переглядів 88 тис.7 місяців тому
Berkeley Math Tournament calculus tiebreaker
I integrated the quadratic formula
Переглядів 408 тис.7 місяців тому
I integrated the quadratic formula
how is e^e^x=1 solvable??
Переглядів 621 тис.7 місяців тому
how is e^e^x=1 solvable??
the first 5 days of calculus 2 but the integrals get harder!
Переглядів 61 тис.8 місяців тому
the first 5 days of calculus 2 but the integrals get harder!
limit of 1/(1-cos(ln(sin(tan^-1(e^(x^2)))))) as x goes to infinity
Переглядів 35 тис.8 місяців тому
limit of 1/(1-cos(ln(sin(tan^-1(e^(x^2)))))) as x goes to infinity

КОМЕНТАРІ

  • @The_real_FBI-007
    @The_real_FBI-007 29 хвилин тому

    I don't even know why I'm watching this.

  • @omaanshkaushal3522
    @omaanshkaushal3522 Годину тому

    Tried solving using desmos. Plotted x+y=8 first. Then plotted x^y = some constant b. The value of b where the two graphs only have one point of intersection is the maximum value of the function, and that came out to be approximately 280.902799

  • @holaqaseesta4241
    @holaqaseesta4241 Годину тому

    Isnt last one sin(π/2+2πk) which always will give one and sin(-3π/2+2πk) which will also end on the positive side of the circumference as its going to the negatives and then the postives? Reasoning like that it would be 1+1 =2

  • @chill4r585
    @chill4r585 2 години тому

    guys jokes aside but how do you know that the limit of a continuous function is a function of the limit of the thing inside it? Is it calc 1 or 2 or 3? I dont remember getting this property when learning limits. Tanks

  • @user-dh1bl7ub7k
    @user-dh1bl7ub7k 2 години тому

    log base 1 does not exist...

  • @eagleraj3126
    @eagleraj3126 3 години тому

    Sir videos help me a lot to make my concept very strong in mathematics love from India❤❤❤❤

  • @chunghimchu3313
    @chunghimchu3313 3 години тому

    The easiest way to calculate sin 15 is sin (45-30) = sin 45cos 30 - cos 45sin 30. 45 and 30 are special angles.

  • @keithmorgan6498
    @keithmorgan6498 3 години тому

    If in doubt iterate! Here are 2 iteration equations for 2 real roots anyway. Use x = 1 to start things off x^5 - 5x + 3 = 0 x^5 = 5x - 3 x = (5x - 3)^(1/5) 1.275 682 204 x^5 - 5x + 3 = 0 x^5 - 5x = -3 x(x^4 - 5) = -3 x = -3/(x^4 - 5) 0.618 033 988 8 (Golden Mean)

  • @chunghimchu3313
    @chunghimchu3313 3 години тому

    I have a question, arctan (♾️) is not only equal to π/2, it also can be 5π/2, how do you prove that π/2 is the unique answer? Thanks

  • @tapllover4667
    @tapllover4667 3 години тому

    I’m too late for this but ever considered adding sinh(x) cosh(x) tanh(x) coth(x) etc, to the integral?

  • @Rain-ju2ge
    @Rain-ju2ge 3 години тому

    I like how my professors doesn't taught me this 🙃 Thank you professor, you are very useful

  • @salvadorsabateromero2258
    @salvadorsabateromero2258 3 години тому

    11:41

  • @vafasadrif12
    @vafasadrif12 6 годин тому

    For each of them you could just multiply both sides by (x-1) for instance: (x-1)(x³+x²+x+1) = (0)(x-1) x⁴-1 = 0 x⁴ = 1 and therefore x = 1 ∠ θ Where θ = 0°,90°,180°,270° Except when θ = 0 we would have x = 1 which is an artifact created when multiplying by x - 1 and not a genuine solution

  • @nirmaljyotieducationclasse9965
    @nirmaljyotieducationclasse9965 6 годин тому

    hey man how did you derive the 2 equation i am having a lot of trouble understanding that . how did you remove mod from the equvalence and all that

  • @rsz90182
    @rsz90182 7 годин тому

    √i = √me if you square bothe sides i = me. Therefore i am me.

  • @abhinavyadav8408
    @abhinavyadav8408 7 годин тому

    we can solve by adding the equations xy+z=40 eq1 xz+y=51 eq2 x+y+z=19 eq3 on adding eq. 1,2,3 x+xy+xz+2y+2z=110 adding 2 on both the sides x(y+z+1) 2(y+z+1)=112 (x+2) (y+z+1)=112 -------equation 4 from equation 3 y+z=19-x substituting y+z=19-x in eq. 4. (x+2) (-x+20)=112 -x^2+18x-72=0 (x-6)(-x+12)=0--------equation 5 from equation 5 x=6, x=12 substituting x=6 in equations 1,2,3 we get 6y+z=40--eq6 6z+y=51---eq7 6+y+z=19 --eq8 from equation 8 y+z=13 from equation 6 z=40-6y substituting z=40-6y in eq. 8 -5y=-27 y=5.4 substituting y=5.4 in equation 8 z=7.6

  • @vedaangkharya6887
    @vedaangkharya6887 8 годин тому

    I found this formula through recursion once, and also number of squares

  • @nairaraika
    @nairaraika 8 годин тому

    you didn't miss a single step, it got way easier to understand

  • @AlbertTheGenius.
    @AlbertTheGenius. 8 годин тому

    I saw the blue pen 😂

  • @alessandrocava4701
    @alessandrocava4701 9 годин тому

    Wow, I'm really glad I watched that video on Euler's equation, otherwise this video would be gibberish.

  • @eustacenjeru7225
    @eustacenjeru7225 10 годин тому

    Welcome

  • @laxmikagapu757
    @laxmikagapu757 11 годин тому

    Pls make the proof for sqrt of a+sqrt of a - sqrt of a so on

  • @piglink10
    @piglink10 11 годин тому

    When you really really love this question

  • @Redstoner34526
    @Redstoner34526 11 годин тому

    You should try the 2011 IMO question number 2 it is very fun

  • @p1xelat3d
    @p1xelat3d 16 годин тому

    Somewhere around 24/25

  • @rafazieba9982
    @rafazieba9982 16 годин тому

    All 5 solutions of the original equation (0, two positive and two negative) are valid. For angles: { 0, 36, 72, 108, 144 } + k * 180 for integer k including zero. For an even k they are 0 or positive and for an odd k they are 0 or negative.

  • @isakpohner124
    @isakpohner124 18 годин тому

    why cant you just write the sin(x) as cos(x-pi/2)

  • @stolenmonkey7477
    @stolenmonkey7477 18 годин тому

    within like 5 seconds of me thinking about it, I was like "y=1" but was also like "that is definitely correct, but way too simple for this to be the answer he gives" lol

  • @Harrykesh630
    @Harrykesh630 18 годин тому

    Feynman's Trick or Leibniz Rule ?

  • @eustacenjeru7225
    @eustacenjeru7225 18 годин тому

    This is very brilliant

  • @colinjava8447
    @colinjava8447 19 годин тому

    It's not that hard, it's just a sector of a circle = (1/3)pi×4^2 MINUS Area of triangle= (1/2)absinC = (1/2)×4^2×sin120 = 8×sqrt(3)/2 = 4sqrt(3) Then just a full circle minus 4 of those D shapes, easy.

  • @a_minor
    @a_minor 19 годин тому

    I think the first step is the reason why this equation truly does not have a solution as a logarithm to the base 1 is not defined (not even in the complex world)

  • @dannyhodson2525
    @dannyhodson2525 20 годин тому

    I was part of the year this question was on 😭

  • @philipwang9084
    @philipwang9084 20 годин тому

    i = EXP(i*Pi/2) or i = EXP(i*(Pi/2+2*Pi)) --> SQRT(i) = EXP(i*Pi/4) or EXP(i*5*Pi/4) --> SQRTi) = Cos(Pi/4) + i Sin(Pi/4) or Cos(5*Pi/4) + i Sin(5*Pi/4) --> SQRT(i) = SQRT(2)/2 + i * SQRT(2)/2 or SQRT(i) = -SQRT(2)/2 - i * SQRT(2)/2

  • @DEYGAMEDU
    @DEYGAMEDU 21 годину тому

    3:32:45 tan θ is wrong, you forgot thats 4x not 4

  • @Poem_arabic
    @Poem_arabic 21 годину тому

    U r so smart Thank you 💗

  • @hpsmash77
    @hpsmash77 23 години тому

    11:55 that transition

  • @rowanhollis8593
    @rowanhollis8593 23 години тому

    george washington

  • @aljoker3053
    @aljoker3053 День тому

    I need this calculateor please🙏

  • @tommyso3823
    @tommyso3823 День тому

    OMG, seeing these questions bring me back memories of me sitting in front of the desk in my room, doing past papers after past papers. Just missed mine by 6 years (Jun 2016)

  • @sashimiPv
    @sashimiPv День тому

    I know I am 5 years late for the party, but shouldn't integral number 31. equal to: -4*sqrt(1-sqrt(x)) + C?

  • @ElioraY-ql4xc
    @ElioraY-ql4xc День тому

    This video deserves the word "ultimate"

  • @jonascaburnay4839
    @jonascaburnay4839 День тому

    i was having a hard time reviewing my instructor's pdf, thank you for this!~

  • @user-mf5nw9qg5r
    @user-mf5nw9qg5r День тому

    ∆ABC, AB=AC=1 and ∠A=36° Let D is on AC such that AD=BD then ∠BDC=∠C=72° and ∆ABC~∆BCD (AA) Let AD=BC=a ( cos72°=√[1-(a/2)²] ) then 1:a=a:(1-a) => a²=1-a => a=(-1+√5)/2 Thus cos72°=√(a+3)/2 =√[2(5+√5)]/4

  • @Welcome_574
    @Welcome_574 День тому

    Thank u sir

  • @thexoxob9448
    @thexoxob9448 День тому

    The no.1 confused me b/c I interpreted log as base 10. Also why do they make ln notation if people still use log for ln anyway?

  • @dawg1744
    @dawg1744 День тому

    This video 'I hate internet math' by doorwaydude is what I consider to be a 'sequel' to this vid. It attempts to explain why these debates exist in the first place (and why some of them are pointless). I really think people in this comment section should have a look if they are still unsure about things like 0.999...=1

    • @cyberagua
      @cyberagua Годину тому

      Thanks, dude! 👍 No problem with dude, I hope?

  • @monawarnaqvi1574
    @monawarnaqvi1574 День тому

    So it doesn't change the fact that I don't like minus and I remove it, and I am still correct

  • @SaloCh
    @SaloCh День тому

    But wait what about limits like lim(1/x) as x->0? From one side it approaches +inf and from another -inf. L'Hopital would say it's equal to 0 but I think most people would still say it's undefined/indeterminate?

  • @SlimThrull
    @SlimThrull День тому

    Find Sin(1), multiply by 72 and you're set! /s