If partial derivative f and fy exist at a point (a, b), then (a) continuous but need not differentiable at (a, b) (b) function is differentiable at (a, b) ()con

If partial derivative f and fy exist at a point (a, b), then (a) continuous but need not differentiable at (a, b) (b) function is differentiable at (a, b) ()continuous and differentiable at (a, b) () None of these O a O b O Od For the f(x, y) = 4 fC0,0) is (a)0 (b) 1 (c) 2 (d)-1 O a Ob O c O d