Find the gradient ∇f\nabla f∇f of f(x,y)=x2yf(x, y) = x^2yf(x,y)=x2y at (2,1)(2, 1)(2,1).
⟨2,2⟩\langle 2, 2 \rangle⟨2,2⟩
⟨4,1⟩\langle 4, 1 \rangle⟨4,1⟩
⟨1,4⟩\langle 1, 4 \rangle⟨1,4⟩
⟨4,4⟩\langle 4, 4 \rangle⟨4,4⟩