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

Answer 1

\[(\cos(\theta) +\cos(\theta))^2 +(\cos(\theta)+\cos(\theta))^2= (2\cos(\theta))^2+(2\cos(\theta))^2\]

Answer 2

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

Answer 3

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

Answer 4

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

Answer 5

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