[cosx(tanx-secx)]
(1-cscx) = sinx
[cosx(sinx - 1 )
(cosx cosx)
------------------------------ = sinx
(1 - 1 )
sinx
divide out the cosx, put bottom over sinx
(sinx -1)
1
------------------ = sinx
sinx - 1
sinx
sinx -1 sinx
--------- * ------- = sinx
1 sinx -1
sinx = sinx proved