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dnt
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Homework Statement
(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
Homework Equations
n/a
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.