For each of the following, find a (piecewise) smooth parametrization of C and compute ∫Cgds.
a) C is the curve y = √9 - x2, x > 0, and g(x, y) = xy2.
b) C is the portion of the ellipse x2/a2 + y2/b2 = 1, a, b > 0, which lies in the first quadrant and g(x, y) = xy.
c) C is the intersection of the surfaces x2 + z2 = 4 and y = x2, and g(x, y, z) = √l + yz2.
d) C is the triangle with vertices (0, 0, 0), (1, 0, 0), and (0, 2, 0), and g(x, y, z) = x + y + z3.