Question

Prove the following trigonometric identities:
sec6θ=tan6θ+3tan²θsec²θ+1

Answer 1

Answer:

Cos255= cos (270-15) = -sin 15

Sin 165=sin (180-15)=sin15

So,

cos255+sin 165

=-sin15+sin15

=0

Answer 2

Answer:

Step-by-step explanation:

• sec 6 θ=(sec 2 θ) 3 =(1+tan 2 θ) 3 =(1) 3 +(tan 2 θ) 3 +3×1×tan 2 θ(1+tan 2 θ)=1+tan 6 θ+3tan 2 θsec 2 θ​