Question

change secant power 4 theta minus secant squared theta in terms of tan theta

Answer 1

$secx^{4} - secx^{2}$
=$secx^{2} (secx^{2} -1)$
$(secx^{2} = 1 + tanx^{2} )$
$(secx^{2} - 1 = tanx^{2} )$
=$(1 + tanx^{2} )tanx^{2}$
=$tanx^{2} +tanx^{4}$