Trig and double angle integration

Thread starter banshee43
Start date Feb 4, 2013
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Angle Integration Trig

Feb 4, 2013

banshee43

Homework Statement

∫sin(t)cos(2t)dt

Homework Equations

cos(2t)=1-2sin^2(t)

The Attempt at a Solution

∫sint(t)(1-2sin^2(t))dt
but where do i go from here? i can't use substitution. or parts?

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Feb 4, 2013

iRaid

cos2x can also = 2cos²x-1, if you make it that, then this is a simple u-substitution..
u=cosx

Feb 4, 2013

banshee43

thankyou very much! i just didnt exhaust my formulas..

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