# Homework Help: Int (e^cost)(sin2t)dt Ahhh

1. Jul 5, 2010

### xibalba1

Int (e^cost)(sin2t)dt Ahhh!!

1. The problem statement, all variables and given/known data
First make a substitution and then use integration by parts

2. Relevant equations
INTEGRAL OF (e^cost)(sin2t)dt

3. The attempt at a solution

the 2t is bothering me.

try subbing u=e^cost

thank you.

2. Jul 5, 2010

### HallsofIvy

Re: Int (e^cost)(sin2t)dt Ahhh!!

I would not use e^cos t. I would use the trig identity, sin(2t)= 2sin(t)cos(t) so that the integral became $2\int e^{cos(t)}cos(t)sin(t)dt$ and use the substitution u= cos(t), then integration by parts.

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