I'm normally ok with these types of questions but this one has got me really stuck. I tried converting to polar coordinates but it gave a horrible integration to carry out for me so I think I've done it wrong. So yeah, any help appreciated .

I couldn't write out the integral on here so I've attached the paper that the question's from (it wouldnt let me attach a JPEG or GIF of the question - why?!). Question 10 .