ALL solution to a triple exponential equation 8^x+4^x+2^x=14

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blackpenredpen

blackpenredpen

Күн бұрын

Пікірлер: 259
@blackpenredpen
@blackpenredpen 3 жыл бұрын
Solving 9^x+3^x=1 👉 kzbin.info/www/bejne/bYHUdY2anr-MncU (calculus tutorials channel)
@축복-l1l
@축복-l1l 3 жыл бұрын
0 x2 0= take isit
@sudirosudiro4218
@sudirosudiro4218 3 жыл бұрын
Proof of Laplace Transform of Dirac Delta kzbin.info/www/bejne/aHisiXyunLZ4mJI
@SuperYoonHo
@SuperYoonHo 2 жыл бұрын
@@축복-l1l hi n sorry bwt ur jokes aren't funny
@b.m.7033
@b.m.7033 3 жыл бұрын
I nailed x=1.
@YTBRSosyalEmre
@YTBRSosyalEmre 2 жыл бұрын
I hammered x=1
@paolobasarini9586
@paolobasarini9586 Жыл бұрын
I pinned x=1
@claws811
@claws811 21 күн бұрын
I smashed x=1.
@nathanielb3510
@nathanielb3510 3 жыл бұрын
I also teach pre-calculus, my favourite part is making bonus questions for quizzes. We're actually covering synthetic division right now! Love your videos.
@blackpenredpen
@blackpenredpen 3 жыл бұрын
Thank you.
@PicklePercyy
@PicklePercyy 3 жыл бұрын
make this a bonus question for your next test
@MUJAHID96414
@MUJAHID96414 3 жыл бұрын
Can you teach me calculas .I'm excited 😄
@fuji_films
@fuji_films 3 жыл бұрын
@@MUJAHID96414 Go to school!
@alberteinstein3612
@alberteinstein3612 3 жыл бұрын
You’re one of those math teachers that post KZbin videos that directly relate to the lessons you’re teaching :) That’s what my Calculus teacher does
@michapodlaszuk9025
@michapodlaszuk9025 3 жыл бұрын
I thought you dropped out at the age of 15
@pezasus
@pezasus 3 жыл бұрын
This reminds me of a mind your decisions question, 4^x + 6^x = 9^x I’m not sure whether you’ve covered it before but it’s really satisfying to solve
@blackpenredpen
@blackpenredpen 3 жыл бұрын
Oh yea that’s a really fun one.
@sharpnova2
@sharpnova2 3 жыл бұрын
that was a nice problem
@lesterdavidoff9869
@lesterdavidoff9869 2 жыл бұрын
How did you solve it
@pezasus
@pezasus 2 жыл бұрын
@@lesterdavidoff9869 I'll give a hint first; try dividing by each of the terms to find something that looks familiar.
@Maths_3.1415
@Maths_3.1415 2 жыл бұрын
Integer solution Solve for x over the integers: 2^x + 4^x + 8^x = 14 Simplify and substitute y = 2^x. 2^x + 4^x + 8^x = 2^x + (2^x)^2 + (2^x)^3 = y^3 + y^2 + y: y^3 + y^2 + y = 14 Subtract 14 from both sides: y^3 + y^2 + y - 14 = 0 The possible rational roots of y^3 + y^2 + y - 14 are y = ± 1, y = ± 2, y = ± 7, y = ± 14. Of these, y = 2 is a root: y = 2 Substitute back for y = 2^x: 2^x = 2 2 = 2^1: 2^x = 2^1 Equate exponents of 2 on both sides: Answer: | | x = 1
@sr.tarsaimsingh9294
@sr.tarsaimsingh9294 3 жыл бұрын
"Blackpenredpen Yay!!!! " I miss that kind of initial startup. 🧐
@andrewlees3946
@andrewlees3946 3 жыл бұрын
That polynomial division is so much easier than the method we were taught! Any chance we can get further explanation about how that works?
@blackpenredpen
@blackpenredpen 3 жыл бұрын
Here’s a video on the comparison between synthetic division and the polynomial long division kzbin.info/www/bejne/nYaze52Ihb50a8k
@alro3553
@alro3553 3 жыл бұрын
It is called ruffini's method if you want to check it out!
@DrDeuteron
@DrDeuteron 3 жыл бұрын
I agree, I was never satisfied with my polynomial division skills, and I blame the method. It has only come up a few times in my work (QCD phenomenology), though.
@raytheboss4650
@raytheboss4650 3 жыл бұрын
nothing better than homemade baked triple exponetial equation for breakfast!
@blackpenredpen
@blackpenredpen 3 жыл бұрын
Hahaha
@janami-dharmam
@janami-dharmam 3 жыл бұрын
constipation or loose motion; you choose!
@raytheboss4650
@raytheboss4650 3 жыл бұрын
@@janami-dharmam i chose sextic polynomial equation
@kavyanshtyagi2563
@kavyanshtyagi2563 3 жыл бұрын
why dont you start teaching mathematics of olympiad level on youtube , you would be the best !!!!
@mastershooter64
@mastershooter64 3 жыл бұрын
I know right, that'd be awesome, and the putnam too!
@justinpark939
@justinpark939 3 жыл бұрын
well, he does have an IMO problem walkthrough at the very least. I asked if he could take in some problems, but he said he was busy for this semester but feel free to give requests via his buisness email (I think I used).
@thomasblackwell9507
@thomasblackwell9507 3 жыл бұрын
What do you mean by that. He is the BEST!
@PubicGore
@PubicGore 3 жыл бұрын
Because he's not good enough for it. I'm not trying to be rude, he's said it himself several times. You should check out Michael Penn, he's very good at explaining and he does tons of math contest problems.
@qsykip
@qsykip 3 жыл бұрын
Olympiad questions are a very different beast. They’re not necessarily hard per se, but there are a lot of clever tricks that you need to learn. Being good at Olympiad questions doesn’t necessarily make you good at uni maths, and the same is true vice versa. Not saying there aren’t a ton of people that are good at both though, just that they are very different skills.
@derwolf7810
@derwolf7810 3 жыл бұрын
1:58 "Okay, how do we solve this cubic equation? Hmm, we cannot factor this; not even by grouping, right?" I would suggest to use the Cardano formula to solve any cubic equation of the form A t^3 + B t^2 + t y + D = 0; although i should admit that the simplification of u and v easily might become hard to find/see, so the results might look awkward. Define a := B/A, b := C/A, c := D/A, p = (-1/3 a^2 + b) q = (2/27 a^3 - 1/3 a b + c) z := u + v = t + a/3. ==> t^3 + a t^2 + b t y + c = z^3 + p z + q (Edit: Corrected this line) If z is of the form u+v (u + v == z) then z^3 + p z + q = z^3 + (-3 u v) z + (- u^3 - v^3) and with delta = (q/2)^2 + (p/3)^2 the following values of u and v are fulfilling the above condition: u = cbrt(-q/2 + sqrt(delta)) and v = cbrt(-q/2 - sqrt(delta)) Then the solutions for t are: t = (u + v) - B/(3 A), t = -(u + v)/2 - B/(3A) + i sqrt(3)/2 (u - v) and t = -(u + v)/2 - B/(3A) - i sqrt(3)/2 (u - v) The values here are: a := B/A = 1, b := C/A = 1, c := D/A = -14, p = (-1/3 a^2 + b) = (-1/3 1^2 + 1) = (-1 + 3)/3 = 2/3, q = (2/27 a^3 - 1/3 a b + c) = (2/27 1^3 - 1/3 1 1 - 14) = (2 - 9 - 378)/27 = -385/27, delta := (q/2)^2 + (p/3)^3 = 148257/(2 3^3)^2, sqrt(delta) = sqrt(148257/(2 3^3)^2) = sqrt(2372112)/6^3, u = cbrt(-q/2 + sqrt(delta)) = cbrt(-(-385/27)/2 + sqrt(2372112)/6^3) = cbrt(1540 + sqrt(2372112))/6 = (7+sqrt(57))/6, v = cbrt(-q/2 - sqrt(delta)) = cbrt(1540 - sqrt(2372112))/6 = (7-sqrt(57))/6, (u + v) = (7+sqrt(57))/6 + (7-sqrt(57))/6 = 7/3, (u - v) = (7+sqrt(57))/6 - (7-sqrt(57))/6 = sqrt(57)/3 So the solutions here for t are: t = (u + v) - B/(3 A) = 7/3 - 1/(3 1) = 2, t = -(u + v)/2 - B/(3A) + i sqrt(3)/2 (u - v) = -7/3/2 - 1/(3 1) + i sqrt(3)/2 sqrt(57)/3 = -3/2 + i sqrt(19)/2 t = -(u + v)/2 - B/(3A) - i sqrt(3)/2 (u - v) = -3/2 - i sqrt(19)/2
@blackpenredpen
@blackpenredpen 3 жыл бұрын
😮 this is so cool!
@janami-dharmam
@janami-dharmam 3 жыл бұрын
You did not explain the steps: A,B,C and D can be reduced to three terms without loss of generality and the roots will be unchanged. It is always possible to remove the quadratic term by a suitable choice of variable t:= t+a; Then we get u^3+p*u+q=0; cf: (a+b)^3-3*a*b(a+b)-a^3-b^3; then the rest falls in place. (p=-3*a*b and q=-a^3-b^3; solve for a and b and x=a+b) Details here: sites.oxy.edu/ron/math/312/14/projects/Fernandez-Gosselin.pdf
@derwolf7810
@derwolf7810 3 жыл бұрын
@@janami-dharmam Yes, i could have explained why that works. I just wanted to give an example analogue to the formula (x_1,2 = (-B±sqrt(B^2 - 4AC))/(2A)) for quadratic equations (A x^2 + B x + C), which typically is also used without explanation. I admit, given that readers might not have heard of that method, an explanation would have been nice. On the other hand, i think the other parts also might need additional explanation and i am too lazy for a full proof (at least in a ascii-text-form), so i only gave a rough overview.
@vannchen9422
@vannchen9422 3 жыл бұрын
I just took a math competition and will appreciate if you went over this problem: what is the sum of (1/2) + (1/3 + 2/3) + (1/4 +2/4 + 3/4) … + (1/100 + 2/100 + 3/100 +4/100 … + 99/100). Thanks and have a great day!
@hannahjamaj531
@hannahjamaj531 3 жыл бұрын
Hmm
@ahotbanana
@ahotbanana 3 жыл бұрын
The more of your videos I watch, the more I see math as an art form. There's more creativity in coming up with and solving these problems than there is in the average pop song
@AliKhanMaths
@AliKhanMaths 3 жыл бұрын
Another great video! Channels like these inspire me to share my own maths content!
@Ironmonk036
@Ironmonk036 3 жыл бұрын
I didn't know about the 2nd channel. Subscribed!
@professorpoke
@professorpoke 3 жыл бұрын
00:10 laughs in minecraft villager
@blackpenredpen
@blackpenredpen 3 жыл бұрын
😆
@TommyLandon
@TommyLandon 3 жыл бұрын
I am not even a math major, or need complex math to make a living, but I always liked watching your videos!!
@blackpenredpen
@blackpenredpen 3 жыл бұрын
Thanks. I appreciate that. 😃
@TommyLandon
@TommyLandon 3 жыл бұрын
@@blackpenredpen Thank YOU for keeping me curious and intrigued! :)
@Maths_3.1415
@Maths_3.1415 2 жыл бұрын
My solution Solve for x: 2^x + 4^x + 8^x = 14 Simplify and substitute y = 2^x. 2^x + 4^x + 8^x = 2^x + (2^x)^2 + (2^x)^3 = y^3 + y^2 + y: y^3 + y^2 + y = 14 Subtract 14 from both sides: y^3 + y^2 + y - 14 = 0 The left hand side factors into a product with two terms: (y - 2) (y^2 + 3 y + 7) = 0 Split into two equations: y - 2 = 0 or y^2 + 3 y + 7 = 0 Add 2 to both sides: y = 2 or y^2 + 3 y + 7 = 0 Substitute back for y = 2^x: 2^x = 2 or y^2 + 3 y + 7 = 0 Take the logarithm base 2 of both sides: x = (2 i π n_1)/log(2) + 1 for n_1 element Z or y^2 + 3 y + 7 = 0 Subtract 7 from both sides: x = (2 i π n_1)/log(2) + 1 for n_1 element Z or y^2 + 3 y = -7 Add 9/4 to both sides: x = (2 i π n_1)/log(2) + 1 for n_1 element Z or y^2 + 3 y + 9/4 = -19/4 Write the left hand side as a square: x = (2 i π n_1)/log(2) + 1 for n_1 element Z or (y + 3/2)^2 = -19/4 Take the square root of both sides: x = (2 i π n_1)/log(2) + 1 for n_1 element Z or y + 3/2 = (i sqrt(19))/2 or y + 3/2 = -(i sqrt(19))/2 Subtract 3/2 from both sides: x = (2 i π n_1)/log(2) + 1 for n_1 element Z or y = (i sqrt(19))/2 - 3/2 or y + 3/2 = -(i sqrt(19))/2 Substitute back for y = 2^x: x = (2 i π n_1)/log(2) + 1 for n_1 element Z or 2^x = (i sqrt(19))/2 - 3/2 or y + 3/2 = -(i sqrt(19))/2 Take the logarithm base 2 of both sides: x = (2 i π n_1)/log(2) + 1 for n_1 element Z or x = log((i sqrt(19))/2 - 3/2)/log(2) + (2 i π n_2)/log(2) for n_2 element Z or y + 3/2 = -(i sqrt(19))/2 Subtract 3/2 from both sides: x = (2 i π n_1)/log(2) + 1 for n_1 element Z or x = log((i sqrt(19))/2 - 3/2)/log(2) + (2 i π n_2)/log(2) for n_2 element Z or y = -(i sqrt(19))/2 - 3/2 Substitute back for y = 2^x: x = (2 i π n_1)/log(2) + 1 for n_1 element Z or x = log((i sqrt(19))/2 - 3/2)/log(2) + (2 i π n_2)/log(2) for n_2 element Z or 2^x = -(i sqrt(19))/2 - 3/2 Take the logarithm base 2 of both sides: Answer: | | x = (2 i π n_1)/log(2) + 1 for n_1 element Z or x = log((i sqrt(19))/2 - 3/2)/log(2) + (2 i π n_2)/log(2) for n_2 element Z or x = log(-(i sqrt(19))/2 - 3/2)/log(2) + (2 i π n_3)/log(2) for n_3 element Z
@nidhiagrawal3354
@nidhiagrawal3354 3 жыл бұрын
In the case where t = 2, you have to put x = 1 + 2nπi/ln(2) because we are no longer only working with reals where n is in the set of integers. For the case where t ≠ 2, we don't need the "+ 2πi" because it's already included in the log. You can also simplify the log by taking the ½ out and making it a - 1.☺️ Edit: I changed the 2πi to 2nπi and said that n is in the set of integers.
@salimahmad3533
@salimahmad3533 3 жыл бұрын
I can't understand your method 🙄. How you use x = 1 +2 πi?. Please explain it in better way .
@nidhiagrawal3354
@nidhiagrawal3354 3 жыл бұрын
@@salimahmad3533 Oh sorry it shouldn't be 2πi, it should be 2nπi/ln(2) because we're working with base 2 not base e. Where n is the set of integers. I was used to working with base e. Here was my thought process at that time. Since ln(x) = y is the same as x = e^y and we know from the Euler's formula that we can add 2nπi to y and e^y won't change. Therefore, ln(x) has infinitely many solutions. Btw ln(x) means natural log of x, which means log base e of x. I just forgot to add the n part. Now there is actually a way to change the base from 2 to e. lb(x) = y ln(x)/ln(2) = y x = e^(ln(2)y) We know from the Euler's formula that we can add 2nπi/ln(2) to y and e^(ln(2)y) won't change. Btw lb(x) means binary log of x, which means log base 2 of x. I hope this makes sense.☺️
@salimahmad3533
@salimahmad3533 3 жыл бұрын
Thank you.
@nidhiagrawal3354
@nidhiagrawal3354 3 жыл бұрын
@@salimahmad3533 No problem.☺️
@chowring
@chowring 3 жыл бұрын
Nice video! Since we are extending the field of solutions to all complex numbers I believe we should add a 2*Pi*k*i where k is any integer to any solution.
@ДенисКосько-н9и
@ДенисКосько-н9и 3 жыл бұрын
didn't know u had another channel now i do. subscribed.
@playdead1255
@playdead1255 3 жыл бұрын
Finally one of these math videos that I can actually understand. Although it's probably only because I am currently in precalc honors.
@inotmark
@inotmark 3 жыл бұрын
Munch's painting is the perfect background to some of those equations.
@hassanalihusseini1717
@hassanalihusseini1717 3 жыл бұрын
Me in my first maths class.... 😃
@elementalgamer9879
@elementalgamer9879 3 жыл бұрын
I'm not from an English speaking country but heard of precalculus and that stuff in tv shows and movies. Now I realise that here in sweden it's just normal maths so found this useful.
@fabriziosantin7420
@fabriziosantin7420 3 жыл бұрын
Shouldn't all the logs be considered complex logs? So, with infinite solutions?
@blackpenredpen
@blackpenredpen 3 жыл бұрын
Yes. And you can see my ln(a+bi) video in the description : )
@cadaver123
@cadaver123 3 жыл бұрын
6:52 Yeah! This is just so cool 🦒❤
@SirboOfficial
@SirboOfficial 3 жыл бұрын
I did it in a different method. I separated 14 into 2^2... and the other side, as well. Then, you can easily see that x=1
@guilhermerocha2832
@guilhermerocha2832 3 жыл бұрын
I live for the "as always that's it" Thank you for your great work!
@julienelson6506
@julienelson6506 3 жыл бұрын
YAY!! You DID become a teacher!
@leun6768
@leun6768 3 жыл бұрын
I feel so proud for solving it but I used the natural logarithm instead
@TH--NguyenMinhTu
@TH--NguyenMinhTu 3 жыл бұрын
I think that method of factoring out cubic equations like that is called Horner’s method in Vietnamese and it’s pronounced the French way
@gregoryzelevinsky9837
@gregoryzelevinsky9837 3 жыл бұрын
Why do you not feel the need to add 2*pi*i*log_2(e)*n to all the solutions? :)
@benjaminhoeckel7590
@benjaminhoeckel7590 2 жыл бұрын
I never knew you could factor like that. I was always taught to use long division, but this is way faster!!!
@ΑΝΤΩΝΗΣΠΑΠΑΔΟΠΟΥΛΟΣ-ρ4τ
@ΑΝΤΩΝΗΣΠΑΠΑΔΟΠΟΥΛΟΣ-ρ4τ 2 жыл бұрын
I mean, if we're talking only about real solution, we could argue that f(x) = 8^x + 4^x + 2^x is constantly increasing, thus it will either intersect with g(x)=14 at one point, ot not intersect with the graph of g(x) at all. By inspection, x=1 is a solution, therefore, it is also the only real solution.
@domanicmarcus2176
@domanicmarcus2176 3 жыл бұрын
At time 4:49, you said "3 minus 28;" shouldn't it of have been 9 minus 28? Either way, the answer is negative 19.
@debblez
@debblez 3 жыл бұрын
is it possible to solve something like 2^x + 3^x + 5^x = 10 ?
@dimitrispapadimitriou9330
@dimitrispapadimitriou9330 3 жыл бұрын
Yes it is
@debblez
@debblez 3 жыл бұрын
@@dimitrispapadimitriou9330 how?
@dimitrispapadimitriou9330
@dimitrispapadimitriou9330 3 жыл бұрын
@@debblez You can solve this equation by bringing 10 on the left side of the equation. So you have: 2^x+3^x+5^x-10=0 Then let f(x)=2^x+3^x+5^x-10 And then you find f(x) monotonicity, which is nondecreasing By finding monotonicity you prove that your function is 1 to 1 (or Injective function) and that your function could have maximum 1 solution for f(x)=0 By looking at the function it's clear that x=1 is a solution for f(x)=0 and thus the only because f(x) is a 1 to 1 function. So the solution to the first equation is x=1 Sorry if there are any mistakes in English I am not a native speaker.
@lucaslucas191202
@lucaslucas191202 3 жыл бұрын
It's really hard to find all answers (complex as well) since you can't just substitute 2^x=t. Then you end up with t + t^(ln3/ln2) + t^(ln5/ln2). I wouldn't even know where to begin. Wolframalpha also just shows the real solution x=1, but that's not really interesting.
@lucaslucas191202
@lucaslucas191202 3 жыл бұрын
Actually this really intrigued me and I continued looking for complex answers. You can prove that the real part of the complex number must be between 1 and about 1.922. The explanation is rather long, so I'll only write it if you want it. I'm also pretty sure there are an infinite amount of complex solutions, but the imaginary components can get extremely high really quick. The reason the question is so hard is the same that there might be an infinite amount of solutions. 2^z and 3^z rotate with different frequencies as you change the imaginary part, and since ln(2) and ln(3) are irrational you will never be able to find a value for the imaginary part that makes them reach the same degree again. So they're wildly unpredictable. I did not discover a way to find the exact solutions, but you can use an algorithm like the one shown in this video kzbin.info/www/bejne/mGipqYOppsuehbs to find approximations.
@fahdfarachi6232
@fahdfarachi6232 2 жыл бұрын
Here is my method : By putting "f" the function in the video. I simply noticed that 14 = 8 + 4 + 2 We have then f(x) = f(1) And since f is increasing strictly on IR+, then it's injective. Meaning that x=1.
@Risu0chan
@Risu0chan 2 жыл бұрын
Don't forget the non principal branches of the logarithm. There is an infinite number of solutions of the form log(blah)/log(2) + k 2πi/log(2), as well as 1 + k 2πi/log(2), for all integers k
@zaprazvan
@zaprazvan 3 жыл бұрын
love ur content man , respect!!
@TreeCube
@TreeCube 3 жыл бұрын
There are actually more solutions! Homework for you, what are those secret solutions?
@TreeCube
@TreeCube 3 жыл бұрын
HINT eˣ is not injective for complex x.
@girlgaming1993
@girlgaming1993 3 жыл бұрын
yes imaginary plane, just throw in 2pi(n) where n is any integer
@girlgaming1993
@girlgaming1993 3 жыл бұрын
oh wait maybe not
@MikehMike01
@MikehMike01 3 жыл бұрын
6
@TreeCube
@TreeCube 3 жыл бұрын
SOLUTION Let's look at the equations we got earlier (using approximations so it's not messy): 2ˣ = 2 2ˣ = -1.5+2.179…·i 2ˣ = -1.5-2.179…·i Let's focus on the first equation: 2ˣ = 2 Recall: e^(2πk·i) = 1 for integers k Using that, we can rewrite the first equation into this (a bit similar to solving sin(y)=sin(x)): e^(x(Log(2)+2πn·i)) = e^(Log(2)+2πm·i), where m and n are integers and Log is the *principal natural logarithm* Then cross the e's: x(Log(2)+2πn·i)) = Log(2)+2πm·i Solve for x: x = (Log(2)+2πm·i)/(Log(2)+2πn·i) *x = (0.693…+2πm·i)/(0.693…+2πn·i)* We can solve the second and third equations similar to how we did the first equation: x = (Log(-1.5+2.179…·i)+2πm·i)/(Log(2)+2πn·i) x = (Log(-1.5-2.179…·i)+2πm·i)/(Log(2)+2πn·i) *x = (0.972…+2.173…·i+2πm·i)/(0.693…+2πn·i)* *x = (0.972…-2.173…·i+2πm·i)/(0.693…+2πn·i)* Turns out there are infinitely many solutions huh? Note: To compute Log(z): Log(z) = ln(r)+iθ You can prove this by writing z as polar coordinates.
@mr.inhuman7932
@mr.inhuman7932 3 жыл бұрын
Okay, so this is unrelated to the video, but I have a question: In the Video about the limit as n-->inf. For (n!/n^n)^1/n you said that 0⁰ is unfefined. You have actually said this multiple times. But everywhere I look it clearly says that 0⁰=1. I'd love a video about that! Also I love this channel! Thanks for all the conent you make for us!
@fedem8229
@fedem8229 3 жыл бұрын
0⁰=1 by convenience (it makes many results such as series and other calculations much simpler), but as a limit lim x→a f(x)^g(x), where both f and g converge to 0 as x approaches a, it is an indeterminate form
@jessehammer123
@jessehammer123 3 жыл бұрын
“Everywhere you look” is wrong. We cannot define 0^0 as its own construct, without more information about its context. Generally, if forced to give a value to 0^0, we choose 1 because saying that 0^0 “equals” one breaks the least stuff and is the most useful in the most contexts. But it’s not necessary to do so, and there are examples of other things you could define 0^0 as. There are contexts in which people define 0^0 as 1 because it’s convenient (for example, in polynomials) and contexts in which people don’t define 0^0 (for example, in analysis-type subjects like calculus).
@mahdiomidiyan3444
@mahdiomidiyan3444 3 жыл бұрын
Could you make a video on how to solve b differential equations like below one ? They're interesting! Especially for our university professors. Thank you! 👌🙏 y' = (2x + y + 4)/(x - y - 7) y - (x + x*y^3) y' = 0
@GaryFerrao
@GaryFerrao 3 жыл бұрын
here you're explicit about the log base 2. what was the result of that poll you had a few months earlier?
@stickmanbattle997
@stickmanbattle997 3 жыл бұрын
I'll spend my 6 years and do maths everyday because of this man
@HamStar_
@HamStar_ 3 жыл бұрын
why did I make it to calc 3 and have never seen synthetic division before
@myuu22
@myuu22 3 жыл бұрын
How did this video come out on the same day that Numberphile made a video about the number 14?
@lily_littleangel
@lily_littleangel 3 жыл бұрын
This is great, but what about x^8 + x^4 + x^2 = 14?
@blackpenredpen
@blackpenredpen 3 жыл бұрын
😮!
@ДенисКосько-н9и
@ДенисКосько-н9и 3 жыл бұрын
let t=x^2, so t^4+t^2+t=14. then use cubic resolvent. and Cardano's formula
@ДенисКосько-н9и
@ДенисКосько-н9и 3 жыл бұрын
@@blackpenredpen why not
@jayparekh8636
@jayparekh8636 3 жыл бұрын
Sir I'm from India & I am big fan of yours. Love You SIR..🤗 Your Teaching is Great..
@chazzbunn7811
@chazzbunn7811 3 жыл бұрын
I know you didn't tell us to pause the video and try this on our own, but I did anyways. I solved it the same way as you, I tutor a lot of pre cal so it came naturally to me.
@blackpenredpen
@blackpenredpen 3 жыл бұрын
Nice 👍
@scottwitoff8932
@scottwitoff8932 3 жыл бұрын
Nice video. Lots of good algebra. And I like The Scream on the wall 😉
@blackpenredpen
@blackpenredpen 3 жыл бұрын
Thanks.
@mariosamson1716
@mariosamson1716 6 ай бұрын
u forgot that u can add 2kpii/ln2 where k is an integer to any of these solutions
@Ba2sik
@Ba2sik 3 жыл бұрын
Thanks for the timestamps!
@danmeyer0552
@danmeyer0552 3 жыл бұрын
I love your videos, but in this video I think you forgot the solutions x=1+(2πni/Ln(2)), where n is an integer.
@alvaromedina1119
@alvaromedina1119 3 жыл бұрын
Wow this was beautiful to watch
@chessematics
@chessematics 3 жыл бұрын
The method of division is ingenious. Can you teach these nice tricks for normal arithmetic some day?
@ΑΝΤΩΝΗΣΠΑΠΑΔΟΠΟΥΛΟΣ-ρ4τ
@ΑΝΤΩΝΗΣΠΑΠΑΔΟΠΟΥΛΟΣ-ρ4τ 2 жыл бұрын
This method is called Horner division. Search it up, it's really practical when it comes to factoring polynomials (especially when it comes to the ones whose degree is greater than 2)
@chessematics
@chessematics 2 жыл бұрын
@@ΑΝΤΩΝΗΣΠΑΠΑΔΟΠΟΥΛΟΣ-ρ4τ thanks for giving the name! I'll be checking it out
@yoav613
@yoav613 3 жыл бұрын
Wolfram also knows,if you ask him nicely
@blackpenredpen
@blackpenredpen 3 жыл бұрын
😂
@TheFutureDothDream
@TheFutureDothDream 3 жыл бұрын
so this equation has two solutions: 1 and the complex solution..?
@Pixics
@Pixics 3 жыл бұрын
You are a math wizard, I liked learning about math that applies to real life scenarios, but in general I'm not that great at it.
@ZipplyZane
@ZipplyZane 3 жыл бұрын
I don't think we need to pretend we don't know that x=1. It helps us factor the cubic polynomial. If x = 1, then t = 2, and thus we know that (t-2) is one of the factors. (I actually did it a bit differently and got (t-1) as one of the factors. I had already divided the whole equation through by 2 as I though that might give me better coefficients on the cubic polynomial. )
@paradox_07
@paradox_07 3 жыл бұрын
Sir u are briliant.. ☺️✨
@violintegral
@violintegral 3 жыл бұрын
Substitutions aren't just for integrals!
@blackpenredpen
@blackpenredpen 3 жыл бұрын
😆 yup!
@jomaryambrosio
@jomaryambrosio 3 жыл бұрын
@Blackpenredpen do you have a playlist where you teach math from the algebras to calculus?
@alanarmstrong3186
@alanarmstrong3186 3 жыл бұрын
I made it 2^(3x)+2^(2x)+2^(x)=14 then lnbase2'd all of it. Added the x's together and somehow once I simplify I get some decimal. Just when I started thinking "finally, an easy one" ....I hear "everyone knows its 1"
@ryanjabell
@ryanjabell 3 жыл бұрын
You and Eddie woo are carrying me through early college math lol
@DimaVaulin
@DimaVaulin 3 жыл бұрын
Brilliant begining of the video 👍😆
@Mathematician6124
@Mathematician6124 3 жыл бұрын
If you don't mind please take an alike equation. 4^x + 6^x =9^x.
@sohffso490
@sohffso490 3 жыл бұрын
My teacher would rage seeing a negative number inside square root
@20icosahedron20
@20icosahedron20 4 ай бұрын
Can't we abbreviate it like this? log₂((-3±i√19)÷2) = log₂(-3±i√19)+log₂(1÷2) = log₂(-3±i√19)-1
@tithyyamnahata4944
@tithyyamnahata4944 3 жыл бұрын
How to apply to be in your classes?
@СтилянПетров-к5в
@СтилянПетров-к5в 3 жыл бұрын
Can you do one of those shorts you used to do about what i! (i factorial) is
@aidenmunro6142
@aidenmunro6142 3 жыл бұрын
Love your videos! :)
@joshuaanoruo973
@joshuaanoruo973 2 жыл бұрын
The laugh at the beginning tho 😂😂😂😂😂😂
@Mathematician6124
@Mathematician6124 3 жыл бұрын
It's really worth it.
@chinchang5117
@chinchang5117 3 жыл бұрын
To solve the equation t^3 + t^2 + t - 14 = 0, just press the calculator, Casio 96 sgplus. Mode 4,3.
@kohwenxu
@kohwenxu 3 жыл бұрын
Lol
@kohwenxu
@kohwenxu 3 жыл бұрын
Understand reference
@RajVerma-vp1rp
@RajVerma-vp1rp 3 жыл бұрын
Imagine the Happiness of those who put x=1 & fortunately got it Correct!! 🤞
@blackpenredpen
@blackpenredpen 3 жыл бұрын
😆
@kingarth0r
@kingarth0r 3 жыл бұрын
What did you think of the problem I sent you?
@shawkathasan2211
@shawkathasan2211 3 жыл бұрын
Sometimes i call you a legend of mathematics 🌚🌚
@SuperYoonHo
@SuperYoonHo 2 жыл бұрын
thanks
@ZipplyZane
@ZipplyZane 3 жыл бұрын
I find synthetic division to be more annoying, in the same way that using matrices to solve systems of equations are. I find it easier conceptually if I can keep the variables around. I actually wound up just doing the long division in my head, term by term.
@richardgratton7557
@richardgratton7557 3 жыл бұрын
Cool!😎 but I also kinda feel like the guy in the picture next to the white board!
@navzarzar
@navzarzar 3 жыл бұрын
3 strictly increasing functions = constant => only one solution = 1
@badman1882
@badman1882 3 жыл бұрын
now i know, why i only got 1 mark out of 3 from that question...
@JasonYJS_xoxo
@JasonYJS_xoxo 3 жыл бұрын
X is 1, isn't it?
@DevGola-tn8yk
@DevGola-tn8yk Жыл бұрын
When he said "but I know " My phone crashed
@lukezeng8734
@lukezeng8734 3 жыл бұрын
When you factor polynomials it is much easier to do it by inspection
@mohamedsamir9527
@mohamedsamir9527 3 жыл бұрын
Man you're great I really love ur videos keep up the great work ❤❤
@Aivo382
@Aivo382 3 жыл бұрын
8+4+2=14 If 8^x+4^x+2^x=14 Then we can say: 8^x+4^x+2^x=8+4+2 So x=1..... This is my solution to this problem trying to not get too complex I think it's not matemathicly valid enough even when the actual X result may be 1
@theophonchana5025
@theophonchana5025 3 жыл бұрын
t = 2^(x)
@nohinbinu5017
@nohinbinu5017 3 жыл бұрын
These q come in kvpy.
@Maks-cw5zy
@Maks-cw5zy 3 жыл бұрын
I dont understand how the (t-2)(t^2+3^t+7). I dont understand where/how he got the -2
@GSHAPIROY
@GSHAPIROY 3 жыл бұрын
4:46 That sounded really weird...
@shifatmat
@shifatmat 3 жыл бұрын
The new thumbnails look nice.
@blackpenredpen
@blackpenredpen 3 жыл бұрын
Thanks.
@davidramos4707
@davidramos4707 3 жыл бұрын
Wolfram Alpha should be a sponsor.
@Caturiya
@Caturiya 3 жыл бұрын
What is the name of "No division" NEVER SAW SUCH a THING. Did you discover it?
@blackpenredpen
@blackpenredpen 3 жыл бұрын
This should be helpful: kzbin.info/www/bejne/nYaze52Ihb50a8k
@funikstv7999
@funikstv7999 3 жыл бұрын
Answer is 1 of course
@Joy-be3gk
@Joy-be3gk 3 жыл бұрын
Interesting!👏
@PeterBarnes2
@PeterBarnes2 3 жыл бұрын
You forgot about all the other solutions! The complex logarithm is multivalued! There are infinitely many solutions for each root of the polynomial.
@dracokinerek
@dracokinerek 2 жыл бұрын
How to solve: 8+4+2=14, x=1 done
@naphatrungaphinya546
@naphatrungaphinya546 3 жыл бұрын
Cant x = 1 ????
@pi4313
@pi4313 3 жыл бұрын
x = 1 easiest problem of my life
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