some easy math problem.. grr

[MillionaireNextDoor]

how do i turn:

antideriv of ((tan[x])^3)((sec[x])^2)

into:

(1/4)tan[4x]+C

i'm missing something simple, i just know it.

 

[biostud]

an eraser and a pen?

 

[MillionaireNextDoor]

nah, got those already

 

[pitupepito2000]

I would first try decomposing the tan and sec into sin and cosines. See if that helps, if not try using integration by parts. If not try taking the derivative of your answer and work backwards.

Hope this helps,
pitupepito

antideriv of ((tan[x])^3)((sec[x])^2)
(1/4)tan[4x]+C

 

[MisterPants]

It's (tan[x]^4)/4+c. sec[x]^2= d/dx tan[x], so you have tan[x]^3dtan. If you can't see it right off, let tanx=u: int[u^3du]=u^4/4+c.