(cos θ + cos θ)2 + (cos θ + cos θ)2
answers
sin2 θ
4
8cos2θ
cos2 θ

Assuming the right expression is

 [cos(theta) + cos(theta) ]^2 + [cos(theta) + cos(theta)]^2, the solution is:

[2cos(theta)]^2 + [2cos(theta)]^2 = 4 [cos(theta)]^2 + 4 [cos(theta)]^2 =startin

= 8 [cos(theta)]^2.

If the starting expression is different, please type it and the list of choices again, making sure that the operators can be understood unambiguosly.