Question

i)
(cos A-1) (cot' A+ 1) = -1​

Answer 1

Answer:

$\huge \red{\bf{answer}} \\ \\ (cot\: A - 1)(cot \: A + 1) = - 1 \\ \\ \implies \: {cot}^{2} A- 1 = - 1 \\ \\ \implies \: {cosec}^{2}A- 1 - 1 = - 1 \: \\ \\ \implies {cosec}^{2} A = 1 \\ \\ A = \frac{ \pi}{2}$