Let w(s, t) = f(u(s, t), v(s, where f, u, and v are differentiable, and the following applies. u(0, −3) = −2 v(0, −3) = −6 us(0, −3) = 4 vs(0, −3) = 5 ut(0, −3) = −8 vt(0, −3) = 8 fu(−2, −6) = −4 fv(−2, −6) = 2