MATLAB: How to simplify the trignometric matrices?

simplifytrignometricwrong

I have tried using "simplify" command. MATLAB simplifies it to some extent but not completely. The code is as below:
if true
  %clc
clear all
syms o l1 l2 l0;
A=[ cos(o)      -sin(o)         1;
  cos(o-120)  -sin(o-120)     1;
  cos(o-240)  -sin(o-240)     1;
  ]
X=inv(A)
W=simplify(X)
end
The anwer of the first element of matrix "W" is shown as
if true
  % -(sin(o - 120) - sin(o - 240))/(2*sin(120) - sin(240))
end
clearly which can be further simplified (by applying formulas of Sin(a-b)) to give answer of Cos(o)… What am I doing wrong here??

Best Answer

Tell the simplify function to keep working on it:
W=simplify(X, 'steps', 20)
Also, as Torsten mentioned, the Symbolic Toolbox trigonometric functions require their arguments be in radians not degrees, so multiply the constants by ‘pi/180’.
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