Hi All, Am struggling with part b of the question on page 283. The inside of the integral in the answer is p(u)+v(u)+d(s+u,w+u) but i dont undertsand why it wouldnt be p(s+u,w+u)+v(s+u,w+u)+d(s+u,w+u) like the example of page 281. Can anyone explain please? Thanks!!