Time left 0:43:30 Round your answers to two digits. The equation 7p' Inp + 8q' Inq =15r' Inr defines r as a differentiable function of p and q in the neighborhood of the point (po, 90, To ) = (e, e, e), i.e., r = r(p, q). Then the first-order partial derivative r (e, e) =