% This is the code, Normally "S" will be an input function.
close all
clc
clear
syms w h
S = 0.1901*(w^(0.425))*(h^0.725);
Dsw = diff(S, w);
Dsh = diff(S, h);
first_term = Dsw*10;
second_term = Dsh*2.3;
Final1 = subs(first_term + second_term, w, 100);
Final = subs(Final1, h, 60);
disp(simplify(Final))