I fx, y) is differentiable at (a, b), then the partial derivatives f, andf, at (a, b) (a) f exists but f, does not exists (b)does not exists but f, exists (c) f

I fx, y) is differentiable at (a, b), then the partial derivatives f, andf, at (a, b) (a) f exists but f, does not exists (b)does not exists but f, exists (c) fand f, both are exists (d) f and f, both are not exists Let