Question

Evaluate the double integral:

Answer 1

\[\int\limits_{0}^{\pi/4} \int\limits_{0}^{5} (ycosx + 2) dy dx\]

Answer 2

the first integral would be integrating with respect to y and then integrate that function wrt x correct?

Answer 3

yes so you integrate y*cos(x) + 2 with respect to y which means that x is a constant in this case. So cos(x) is a constant as well.

Answer 4

Ooh nevermind, I know where I messed up. My resulting function was y^2cos(x) + 2y but I forgot the 2 underneath the y^2 term

Answer 5

It's always good to check your integration by differentiating to get back to the original

so if you derive y^2 you would get 2y instead of y. The 1/2 is to get y.

Answer 6

Yeah, I should really make that a habit. Thanks for the help anyways :)

Answer 7

you're welcome