Let S be the surface in R defined by f x y z 0 The tangent plane of S at 2 9 1 is defined by 7 x 2 9 y 9 z 1 0 a Given the equation of the tangent plane to S enter in the box below a column vector v that can be the gradient of fat 2 9 1 V IE V Enter the column vector in the form 1 2 3 b Let g x y z 14x 4y 4z 384 Prove that the surface T defined by g x y z 0 is tangent to the surface S at the point 2 9 1 You don t need to show all computations but you must describe the steps of your proof 1 4