Question

int sen(2y)-sen(y) dy, y=0..1. Please, I'm stuck.

Answer 1

That's all I could do. I don't see the problem.

Answer 2

what's sen?

Answer 3

you mean sine function here?

Answer 4

sin, sorry. in portuguese is "sen"

Answer 5

ah okay

Answer 6

why you mentioned y=0...1?
Ate any rate
do sin(2y)=2sinycosy
sin2y-siny=siny(2cosy-1)

Answer 7

then do U-Substitution
u=2cosy-1 ===> du=-2sinydy
so int (2cosy-1)sinydy=-1/2int (udu)=-1/2 [1/2u^2]+C
=-1/4(2cosy-1)^2+C
you extend it further

Answer 8

Thank you @xapproachesinfinity, I was wrong because I was using the values in degrees, but the correct way is in rads. It wasn't matching with Wolfram.

Answer 9

why are you using values anyway? you were asked to find the integral correct?
so i don't see the reason to use those values unless the question stated to do so