2. You are given the following function z = f(x, y) = ex cos(y). Also, x(t) and y(t) are known implicitly via the following equations: x2 +y2 - th = 1, xy + cos(y) +t = 0. Find dz /dt for all t such that the determinant of the Jacobian is non-zero. 3. You are given that the function z = f(x, y) is implicitly defined by 2c2 + 232 - 22 = 1. Calculate dz, Zx, and Zy