Question

9 cosec² a -9 cot² a​

Answer 1

Step-by-step explanation:

$9 {cosec}^{2} a - 9 {cot}^{2} a$

$= 9( {cosec}^{2} \: a \: - {cot}^{2} \: a)$

$= 9 \times 1 \: \: \: \:$

$= 9$