Search code examples
matlabtrigonometrysymbolic-math

Simplify equation according to trigonometric rules

I was wondering if there was a way to automatically display cosine/sine of the sum of symbolic variables. I'm multiplying symbolic matrices and in one cell of the result I have something like

cos(A)*cos(B)-sin(A)*sin(B)

where A and B are my symbolic variables. Is there a way to automatically display in every occurrence of that the actual cosine of the sum such that the cosine identity is given?

cos(A+B)
Solution

  • Use simplify

    syms A B
simplify(cos(A)*cos(B)-sin(A)*sin(B))
ans =
cos(A + B)