Problem. 9 : Find the first partial derivatives of the function f(x, y) = 1x//1+y fz = (1+y^4)^(1/2) fy = (4y^3)/(2(1 +y14 X Problem. 10 : Find the first partial derivatives of the function f (x, y, z ) = yz" + xy' tryz + xz fz = y^2+ xy^2+yz + X fy = z^5+zyx+XZ X ? f = = Problem. 11 : Evaluate the first partial derivatives of the function at the given point