@sonukg4india Factor the numerator into (cos^2x+sin^2x)(cos^2x-sin^2x). Expression in the denominator cancels and you’re left with cos^2x+sin^2x, which is equal to 1
@sonukg4india We’ll call the intersection between the two lines creating the unknown angle point F. Now look at triangle ABE. It’s an isosceles triangle because AB=AE. If angle A is 60+90=150 deg, then angle B is 15 deg. For triangle ABF, x=180-45-15=120 degrees