Consider the following code:
TC = L + (1 - q) + SC + Ca +
Cr + (Exp[1 - RealAbs[1 - \[Mu]/Subscript[y, 0]]])*
MC + ((Exp[(Subscript[\[Sigma], 1] - \[Sigma])/(
Subscript[\[Sigma], 1] - Subscript[\[Sigma], 2])]) - 1)*DC
n = D[TC, {{\[Sigma], \[Mu]}}]
Solve[n == 0 // Rationalize, {\[Sigma], \[Mu]}]
I need to solve the equation, but running so long.