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a golden integral 

Dr Peyam
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a golden trig integral
We calculate the integral of sin(x)+cos(x)/sin^5(x)+cos^5(x) from 0 to pi/2 using first a u-substitution (or u-sub) followed by a trigonometric substitution, and the Gamma function or Euler's identity. The result involves square roots and the golden ratio, which was used in the Renaissance as a standard of beauty. This is a must-see for any calculus lover or any lover of gold and beauty, enjoy!
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12 окт 2024

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Комментарии : 34   
@dean532
@dean532 2 дня назад
Infact, A golden rule and word of encouragement to some folk here (who still look down upon themselves) : there a many ways to solve most integrals (unless a complex one or something highly geometric like the forms etc etc) so nobody needs to panic; start somewhere! Most of my “frustrations were encountered because I tried to do things in my head-I was to lazy to even pull up a piece of paper. It was some form of math procrastination that I had because of the fear of failure before even beginning to solve anything! So start somewhere!
@SbF6H
@SbF6H 2 дня назад
I agree, because I have that procrastination as well. It's often a great challenge to understand where to start.
@maths_505
@maths_505 15 часов назад
Glad to see you doing more integrals. Excellent work.
@theproofessayist8441
@theproofessayist8441 2 дня назад
This is giving me good flashbacks of your plastic ratio and metallic ratio videos.
@drpeyam
@drpeyam 2 дня назад
Good times 😊
@Cyrus-cnp
@Cyrus-cnp 2 дня назад
You are rocking that shirt, I love it! nice video!
@emanuellandeholm5657
@emanuellandeholm5657 2 дня назад
Dr Peyam has the best shirts in all of math tube.
@drpeyam
@drpeyam 2 дня назад
Thanks so much!! 😊
@bjornfeuerbacher5514
@bjornfeuerbacher5514 2 дня назад
I tried to reduce the fraction, using sin^5(x) + cos^5(x) = (sin(x) + cos(x)) (sin^4(x) - sin^3(x) cos(x) + sin^2(x)cos^2(x) - sin(x)cos^3(x) + cos^4(x)), and then got stuck immediately. :D
@slavinojunepri7648
@slavinojunepri7648 2 дня назад
You may express sin^4 + cos^4 in terms of sin^2 and cos^2, and use the trigonometric identity (sin^2 + cos^2 = 1) to simplify further. A Weierstrass substitution (t=tang(x/2) would then turn the integrand into a rational function, which would be less difficult to integrate.
@bjornfeuerbacher5514
@bjornfeuerbacher5514 2 дня назад
@@slavinojunepri7648 Thanks. :) I really should have remembered the Weierstrass substitution, some years ago, I've used it several times myself.
@slavinojunepri7648
@slavinojunepri7648 2 дня назад
@@bjornfeuerbacher5514 As the saying goes: "If you don't use it, you lose it". I remember the Weierstrass substitution solely from watching these math channels recently.
@dan-florinchereches4892
@dan-florinchereches4892 9 часов назад
@@slavinojunepri7648 I have had an underappreciated math teacher during my high school days. All my colleagues were annoyed cause he was a bit exigent of a 70 year old man. He tried to help us with exercises for our 12th year exam and altough not part of the curriculum he taught us Weierstrass substitution. He said if you don't see immediately a simple solution for a trigonometric integral just use this and stop wasting exam time. He also showed us the Euler substitution during class to prepare us for any eventuality
@thomasjefferson6225
@thomasjefferson6225 16 часов назад
This is REAL MATH!!! I love it. Much better to do something like this than Lets define a function f: X -> Y such that X has the finite compliment topology and Y is the standard topology of the real line, when is this function continous? (constant function, or when the preimage of Y is finite)
@drpeyam
@drpeyam 11 часов назад
That sounds like a homework problem to me :P
@thomasjefferson6225
@thomasjefferson6225 10 часов назад
@@drpeyam no homework in my European university. One exam at the end. Its me attempting to learn on my own :p
@CDChester
@CDChester 23 часа назад
if i dare say you were sparkling
@drpeyam
@drpeyam 11 часов назад
Thank you!!
@ajiwibowo8736
@ajiwibowo8736 2 дня назад
But doc, <a href="#" class="seekto" data-time="682">11:22</a> shouldn't it be sqrt((5+sqrt(5))/5) instead of sqrt((5+sqrt(5))/sqrt(5))??
@dugong369
@dugong369 День назад
@@drpeyamDr Payam you are correct, you just put a 5 in the denominator and then put everything over a common denominator of sqrt(5) all in one step. I thought there was an error there myself, but when I did it myself I saw what was happening. Also checked the numerical result on Wolfram. BTW, sin(pi/5) = (1/2)sqrt(1/phi)sqrt(sqrt(5)) and sin(3pi/5) = (1/2)sqrt(phi)sqrt(sqrt(5)). As you know, anything involving phi can be written in various ways. sin(pi/5) = (1/2)sqrt(1+phi^-2) and sin(3pi/5) = (1/2)sqrt(1+phi^2)
@drpeyam
@drpeyam День назад
@dugong369 Thank you so much!!
@nicogehren6566
@nicogehren6566 2 дня назад
nice approach
@drpeyam
@drpeyam 2 дня назад
Thank you :)
@wychan7574
@wychan7574 21 час назад
<a href="#" class="seekto" data-time="450">7:30</a> v^(-4/5)/(1+v)=v^(-4/5)(1-v+v^2-v^3+…)
@holyshit922
@holyshit922 2 дня назад
With t = tan(x) substitution we can calculate indefinite integral
@drpeyam
@drpeyam 2 дня назад
That’s what I’m doing I think
@ronbannon
@ronbannon День назад
Euler's reduction formula is only valid if m is not an integer.
@drpeyam
@drpeyam День назад
Yes that’s what I meant to say
@Wielorybkek
@Wielorybkek 2 дня назад
*snap snap* 🎶
@dudl2945
@dudl2945 2 дня назад
An integral from 0 to ( Dr Peyam / Dr am) / 2
@drpeyam
@drpeyam 2 дня назад
Awwwwww ☺️
@phill3986
@phill3986 2 дня назад
Nice 👍👏
@jyotsanabenpanchal7271
@jyotsanabenpanchal7271 День назад
😯
@dnd2008yi
@dnd2008yi 7 часов назад
I'm a high schooler Dont know gamma function
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