Find all the first and second order partial derivatives of f

Find all the first and second order partial derivatives of f(x, y) = 5 sin(2x + y) - 5 cos(x - y). = fx = = fy = = f x x = = f y y = = f y x = = f x y =

Solution

when we r partial differentiating with respect to x then y should be constant and vice-versa by following this we get a)10cos(2x+y)+5sin(x-y) b) 5cos(2x+y)-5sin(x-y) c)-20sin(2x+y) + 5cos(x-y) d) -5sin(2x+y) + 5cos(x-y) e) -10sin(2x+y) - 5cos(x-y) f) -10sin(2x+y) - 5cos(x-y)