Question

cot2A-1/sin2A is equal to​

Answer 1

$cot2A - \frac{1}{sin2A} \\ \\ = \frac{cos2A}{sin2A} - \frac{1}{sin2A} \\ \\ = \frac{cos2A - 1}{sin2A} \\ \\ = \frac{1 - 2 {sin}^{2}A- 1 }{sin2A} \\ \\ = \frac{ - 2 {sin}^{2} A}{2sinAcosA} \\ \\ = - \frac{sinA}{cosA} \\ \\ = - cotA$