Q.
A. cosec α [tan(n + 1)α – tan α]
B. sec α [tan(n + 1)α – tan α]
C. 1/2 sec α [tan(n + 1)α – tan α]
D. 1/2 cosec α [tan(n + 1)α – tan α]
E. None of the above
Correct choice: D
Explanation: