Inactive Tutor answered 11/10/15
Tutor
New to Wyzant
Left side = (secx+tanx)3(secx-tanx)3(secx-tanx)
= [(secx+tanx)(secx-tanx)]3(secx-tanx)
=(sec2x- tan2x)3(1/cosx-sinx/cosx)
=1(1-sinx)/cosx
=(1-sinx)/cosx