Calculate the Double Integral

[jenn9580]

I began integrating in respect to y, so that 5x could be pulled out as a constant. Then I used substitution. Then I integrated in respect to x. My final answer was wrong according to my online homework. I believe my problem is a simple mistake in integration but I am not seeing it.

[DrMike]

Nor can we, at the moment...

... but we might be able to help if you could type in some of your intermediate steps....

[BigGlenntheHeavy]

[jenn9580]

Thanks!! I made a rookie mistake! I didn't expand the first cos(x+y) correctly on line 2. I feel like an idiot.

[jenn9580]

Nevermind. I see it now!