Question

Simplify cos(x-y)+cos(x+y)÷cosx

Answer 1

Okay, your equation is unclear. Is it
\[\frac{\cos(x-y)+\cos(x+y)}{\cos x}\]

What you wrote is
\[\cos(x-y)+\frac{\cos(x+y)}{\cos x}\]
when order of evaluation is taken into account.

Answer 2

It is the first question