Pls help me to solve this question

a) Find the first and the second-order partial derivatives for f(x, y) = 2x+y + sin xy. Show that fxy = fyx. (10 Marks) b) Find the slope of the surface, f(x,y) = 1 - (x - 1)2 -(y - 2) at the point (1,2,1) in the x-direction and in the y-direction