Why does Matlab not simplify this further?

I want Matlab to simplify the first partial derivative of the following function:

With the arguments of the function repressed, the first partial derivative with respect to is

Matlab gives me the correct derivative but then does not simplify it further:

clear, clearvars
syms x1 x2 p1 p2 l C rho
syms f(p1,p2)

f(p1,p2) = (l.^(1/(1-rho)) *(p1).^(rho/(rho-1))+(1-l).^(1/(1-rho))*(p2).^(rho/(rho-1))).^((rho-1)/rho)

f(p1, p2) = 

C = f(p1,p2)

C = 

x2 = (diff(f,p2))

x2(p1, p2) = 

simplify(x2,'Steps',10)

ans(p1, p2) = 

I tried to define C=f(p1,p2) but it doesn't help. Any ideas what I can do here?

Answer 1

[Star Strider]

Increase the ‘Steps’ value. It will then continue simplifying until it cannot simplify further, or reaches the maximum ‘Steps’ iteration limit. I use 500 here (as I do usually), however it can be either more or less than that, depending on the result you want. (In this instance, increasing it does not change the result.)

Try this —

clear, clearvars
syms x1 x2 p1 p2 l C rho
syms f(p1,p2)

f(p1,p2) = (l.^(1/(1-rho)) *(p1).^(rho/(rho-1))+(1-l).^(1/(1-rho))*(p2).^(rho/(rho-1))).^((rho-1)/rho)

f(p1, p2) = 

C = f(p1,p2)

C = 

x2 = (diff(f,p2))

x2(p1, p2) = 

simplify(x2,'Steps',500)

ans(p1, p2) = 

.