Mark the correct alternative in the following:
If , then cos x is equal to
Given:
Let cosec x =a, cot x = b
∴ According to the question
⇒
But, cosec2x –cot2x =1
⇒ a2 – b2 = 1
⇒ (a-b) (a + b) = 1
⇒ a + b=2
a-b =1/2 …(1)
a + b =2 …(2)
Adding (1) and (2)
2a = 1/2+2
⇒ a = 5/4
Cos2x = 1 – sin2x