# Commentary on "Simplify trig expressions with the double angle formula"

A bit of reflexion leads me to propose a "brute force" answer to a question wher the answer could be divined with a bit of "intuition".

The original question was :

I am trying to simplify the following expression in sage:

(sqrt(3)/3

cos(x)+1/3sin(x))the resulting expression should be:

2/3*cos(pi/6-x) .simplify_full(), trig_reduce(), or simplify_trig() cannot produce this simplification.

Is sage currently capable of doing this?

See below for the steps of the solution. Comments, criticisms and even lazzi welcome...