Problem with basic integration review

[WhataRecch]

I'm in a second year Calculus class, and we're doing review from first year integration, and it's just unbelievable how easily this stuff leaves your memory. I shouldn't have thrown out last year's notes.

I can't for the life of me remember what techniques I'm suppose to use to integrate:

(((x^2) + 1)^(1/2))dx and (cos(x)^4)dx

 

[lanedance]

1) I'd try a trig sub, 2) Use some trig identities to simply it to lower orders of cosx

 

[hunt_mat]

For the first use x=tan u for the second use cos^{2}x=(1+cos2x)/2 three times