civil engineering mathematics

Oz 1. Given z = vx2 - ry, find Oz and ay when r = 4 and y = 3. of a2f a2 f 2. If f(x, y) = x In(3x + 2y), find ay' dy2 and ardy 3. Find all critical points of f(x, y) = 2x3 - (x - y)2 -6y and classify each point as a local maximum, local minimum or a saddle point by using partial derivatives. 4. Evaluate the following integrals. (a) , a(x -y) dady. (b) filo yev-dady. 5. Evaluate the following double integral /1 (3x - 2y) dA, where R is the region bounded by the lines r = 0, r + y = 3 and y - a = 1