Q40 of 268 Page 5

Prove the following identities

Taking LHS

[multiplying and divide by conjugate of 1– sinθ in 1^st term and 1+sinθ in 2^nd term]

[∵ cos² θ + sin² θ = 1]

= 2 sec θ

=RHS

Hence Proved

Prove the following identities

If secθ + tanθ=m and sec θ – tanθ = n, then prove that

If cosθ + sinθ = 1, then prove that cosθ – sin θ = ± 1.