# How do you verify the identity tan^4x+tan^2x-3=sec^2x(4tan^2x-3)?

${\sec}^{2} x = \left(1 + {\tan}^{2} x\right)$
$R S = \left(1 + {\tan}^{2} x\right) \left(4 {\tan}^{2} x - 3\right)$
$R S = 4 {\tan}^{2} x - 3 + 4 {\tan}^{4} x - 3 {\tan}^{2} x$
$R S = 4 {\tan}^{4} x + {\tan}^{2} x - 3 =$ Left side.