Question

How do you verify cos(x−y)−cos(x+y)=2sinxsiny?

Answer 1

Hola!!⤵️⤵️

⭕cosx cos y + sin x sin y - cos x cos y + sin x sin y = 2sin x sin y

HENCE PROVED.

APPLY THE PROPERTY OF cos (a + b) = cos a cos b - sin a sin b AND cos (a - b) = cos a cos b + sin a sinb✔✔