Evaluate
[tan(180+x)]/[sin(180-x)] times [tan(90+x)]/[cos^2(180+x)] times sin(-x) - 1

=(tanx)/(sinx) times (-tanx)/[cos^2(x)] times -sinx - 1

= 1/cosx times -sinx/cos^3(x) times -sinx -1

=sin^2(x)/cos^4(x) - 1

im stuck at this point can someone help me out.