Consider the function fx y 4radicx2 y2 find the gradient

Question

Consider the function f(x, y) = ⁴√(x² + y²)

(a) Find the gradient vector of the function at the point (1, 1).

(b) Find the equation of the tangent plane at the point (1, 1)

I've tried to solve the gradient vector of the function by trying to differentiate the x and y values of the unction.  I'm just unsure how to do this when the function is a fourth root factor.  Any assistance would be valuable.