3. (30pts) The following questions are about line integrals. (a) (15pts) Let F(x, y, =) = (-y, ry, 0) and C be the curve of the intersection of z = a + y and z = 2r such that C is oriented counterclockwise as viewed from above. Verify Stokes' Theorem by evaluating both the line integral F. dr and its corresponding surface integral JJ curlF . dS in Stokes' Theorem. (b) (15pts) Evaluate fo F . dr, where F(r, y, 2) = (y' + sin(e?), 23 + In(6+y'), x3) and the curve C is given by r(t) = sin ti + costj + sin(2t)k, 0