### 2.21.5 Simplify : `simplify`

`simplify` simplifies the expression.
As with all automatic simplifications, do not expect miracles, you will have to use specific rewriting rules if it does not work.
Input :

`simplify((sin(3*x)+sin(7*x))/sin(5*x))`

Output :

`4*(cos(x))```^```2-2`

Warning `simplify` is more efficient in `radian` mode (check `radian` in the `cas` configuration or input `angle_radian:=1`).