Q11 of 268 Page 5

Prove the followings identities:
(1 + cos θ)(1 – cos θ) = sin²θ

Taking LHS =(1 – cosθ)(1+ cosθ)

Using identity , (a + b) (a – b) = (a² – b²) , we get

= (1)² – (cosθ)²

= 1 – cos² θ

= sin² θ [∵ cos² θ + sin² θ = 1]

= RHS

Hence Proved

If x cos A = 1 and tan A = y, then what is the value of x² – y².

Prove the followings identities:

(1 – sin θ)(1 + sin θ) = cso² θ

Prove the followings identities:

Prove the followings identities:(1 + cos θ)(1 – cos θ) = sin2θ