Please help with practice problem 1.

Let f(x, y, z) = x*y' + z and x = s', y = st , and z = s't. (a) Calculate the primary derivatives of of of dx ' dy ' dz (Use symbolic notation and fractions where needed.) of Ox af = dy az =\f(c) Compute using the Chain Rule. of dx of dy , of dz + as Ox ds + dy as dz ds (Use symbolic notation and fractions where needed.) fe = as