(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

(dont know how to make the integral sign so bare with me please)

i will use | to signify the integral sign:

here is my problem:

|(sinx)(cos)dx

2. Relevant equations

n/a

3. The attempt at a solution

ok this is what i did:

first i changed it to (1/2)sin2x because sin2x=2sinxcosx

so now i have:

|(1/2)sin2xdx

then i said u = 2x and du=2dx

so now i have:

|(1/4)sinudu

which is:

(1/4)(-cos u) + C

which is:

(1/4)(-cos2x) + C

where is my error?

also, can someone give me a brief overview of the best strategy to figure out what type of integration to use? what do you look for to know when to use trig substituion, integration by parts, u-substitution, etc...

ie, how do you know? thanks.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: What did i do wrong in my integration?

**Physics Forums | Science Articles, Homework Help, Discussion**