Prove the following trigonometric identities:
cosec Acosec A−1+cosec Acosec A+1=2sec2A
Ans:
To prove,
(cosecA)(cosecA−1)+(cosecA)(cosecA+1)(cosecA)(cosecA−1)+(cosecA)(cosecA+1) = 2sec2 A
Considering left hand side (LHS),
= (cosecA)(cosecA+1+cosecA−1)(cosec2A−1))(cosecA)(cosecA+1+cosecA−1)(cosec2A−1))
= (2cosec2A)cot2A(2cosec2A)cot2A
= (2sin2A)sin2A.cos2A(2sin2A)sin2A.cos2A
= 2cos2A2cos2A
= 2sec2A2sec2A
Therefore, LHS = RHS
Hence proved