Medal and follow if you can help me solve this.

(cos θ + cos θ)^2 + (cos θ + cos θ)^2

a)sin2 θ
b)4
c)8cos2 θ
d)cos2 θ

Question

Medal and follow if you can help me solve this.
	
(cos θ + cos θ)^2 + (cos θ + cos θ)^2 

 	
	a)sin2 θ
	b)4
	c)8cos2 θ
	d)cos2 θ

jhannybean · Answer

$$(\cos(\theta) +\cos(\theta))^2 +(\cos(\theta)+\cos(\theta))^2= (2\cos(\theta))^2+(2\cos(\theta))^2$$

anonymous · Answer

Ah okay so in my head i just got 8cos2 θ

anonymous · Answer

is that correct in my math? I normally never make calculation mistakes

jhannybean · Answer

yeah that's the correct answer, but can you explain to me how you got it?

anonymous · Answer

I just did it in my head. Distributed it. Maybe i'm lucky?