Question

(sina+cosa)^2-1/tana-sina.cosa=2cot^2a​

Answer 1

$= \frac{( {sina + cosa})^{2} - 1 }{tana - sinacosa} \\ = \frac{1 + 2sinacosa - 1}{ \frac{sina}{cosa} - sinacosa } \\ = \frac{2sinacosa}{ \frac{sina - sina {cos}^{2}a }{cosa} } \\ = \frac{2sina {cos}^{2} a}{sina(1 - {cos}^{2} a)} \\ = \frac{2 {cos}^{2}a }{ {sin}^{2} a} \\ = 2 {cot}^{2} a$