Question

(ii) (1 + cot A)2 + (1 - cot A)2 = 2 cosec2 A​

Answer 1

(1 + cot A)² + (1 - cot A)² = 2 cosec² A

L.H.S = (1 + cot A)² + (1 - cot A)²

​1+ cot² A + 2 cot A + 1 + cot² A - 2 cot A

2 + 2 cot² A

2(1 + cot² A)

2 cosec² A                         (1 + cot²Ф = cosec ² Ф)

hence ,  L.H.S = R.H.S