Question

(iii) 2 cos2 A - 1 = 1 - 2 sin2A​

Answer 1

Step-by-step explanation:

$2 { \cos( \alpha ) }^{2} - 1 = 2( { 1 - \sin( \alpha ) }^{2} ) - 1 \\ = 2 - 2 { \sin( \alpha ) }^{2} - 1 \\ = 1 - 2 { \sin( \alpha ) }^{2}$