MATLAB: How to force simplify function I want

simplifysubssymbolicSymbolic Math Toolbox

I have a problem about both simplify and subs functions.
  1. Simplify function is not working in the following example.
syms mu B cc M M_bar E V_N sigma_1;
sigma_1 = sqrt((M+M_bar-4*E*V_N)^2+(2*mu*B)^2);
cantSimplified_Var = simplify(sqrt(4*B^2*mu^sym(2) + 16*E^sym(2)*V_N^2 - 8*E*M*V_N - 8*E*M_bar*V_N + M^2 + 2*M*M_bar + M_bar^2));
isequal(expand(sigma_1),cantSimplified_Var)
    ans =
  logical
   1
isequal(sigma_1,cantSimplified_Var)
    ans =
  logical
   0
2. I want to continue with my new defined function. For example,
syms A B C
A = B^2;
C = A + B^2
    C =
 
    2*B^2
Here, I want to see equation like "C = 2*A". Is it possible?
It is related to my first question, because if I can see the expression like "C = 2*A", I will continue my calculation whether MATLAB simplify it correctly or not.

Best Answer

Tell MATLAB to keep slimplfying until it cannot simplify it further (or reaches the iteration limit), then test equality with the isAlways function: 
syms mu B cc M M_bar E V_N sigma_1;
sigma_1 = sqrt((M+M_bar-4*E*V_N)^2+(2*mu*B)^2);
cantSimplified_Var = simplify(sqrt(4*B^2*mu^sym(2) + 16*E^sym(2)*V_N^2 - 8*E*M*V_N - 8*E*M_bar*V_N + M^2 + 2*M*M_bar + M_bar^2), 'Steps',500);
Test = isAlways(sigma_1 == cantSimplified_Var)
producing: 
Test =
  logical
   1
.
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