Trigonometric Integrals - Part 4 of 6

Trigonometric Integrals - Part 4 of 6. In this video, the 'cookie cutter' case of products of odd powers of tangent and powers of secant is discussed. For more free math videos, visit http://PatrickJMT.com

Category:

Education

Tags:

• calculus
• math
• trigonometric
• integral
• integration
• trig
• function
• sine
• cosine
• justmathtutoring.com
• austin
• example

[jaleed]

for tan^5x, can we change it to sin^5x/cos^5x, and intergate. Will it be the same answer

[patrickJMT]

@jaleed well, after you change it, how do you integrate it?

[da1booger13]

Hmmm, patrick, at 7:20, shouldn't there be a 1/secx there? I say this because of when the 'u' was taken to equal secx. In that case, only the tanx would have remained in the integrand. Thus, when taking the derivative of the u value(secx) which equals 'secxtanx', that derivative would have only crossed out the tanx in the integrand. So it would seem to leave you with a 1/secx. Anyway, I might be brutally wrong, please take me in the right direction if so.

[patrickJMT]

@da1booger13 you are probably right, i am too lazy to rewatch

[beshjm]

awesome, i just finished th 6 parts, will go to the exam in one hour and this part (trig integral subs) drove me crazy, but not anymore ;)

[patrickJMT]

excellent : )

[mjk2492]

Seriously, I love you man.

[BrothaDavid]

Dammit, I don't care if you're a Mormon or not, just let me watch Patrick. Go away.

[Angelgrrl04]

@1:57 - It said to save tanxsecx, and use tan^2x=sec^2x-1 to replace it. Yet you replaced tan^2x with sec^2x-1. Your first three videos you used what you save and replaced it with. But in this one, you just replaced the tan^2x. Why is that?

[redrum41987]

I'm blowin thru these now, thank you

[erikaalysse]

@jaleed you would do u-substitution and let cosx = u,

[jaleed]

@patrickJMT Strip out a sin, and replace sin^4x with the identity sin^2x=1-cos^2x. Use u sub to take out the stripped sin. and then intergate?