Can I enter identity solution in trig and give me answer?

edit

Hi,

it is possible, just try

var('x')
((cos(x)-sin(x))^2).trig_simplify()

which will result in

-2*cos(x)*sin(x) + 1

since sin(x)^2+cos(x)^2=1 (I think you mean this formula with the trigonometric identity).