Cos(a-b)cos(a+b)?

Question

Cos(a-b)cos(a+b)?

Answer 1

This suspiciously looks like a math question, trespassing in the Anthropology Section!

Answer 2

Use the double angle formula twice

cos(a+b) = cos(a)cos(b)-sin(a)sin(b)

then simplify.

Answer 3

cos^2a-sin^2b

or

cos^2b-cos^2a

want proof then mail me

Answer 4

I'll see your,,,cos(a-b)cos(a+b)? and raise you:

Ω∈ D

(ii) A,B ∈ D,A ⊆ B ⇒ B \ A ∈ D

(iii) An ∈ D,An ⊆ An+1, n ≥ 1 ⇒

+∞



n=1

An ∈ D

Your move!

Answer 5

Can you please ask a question?