Question

prove that cosx/1-sinx=tan(π/4-x/2)

Answer 1

Rhs = tan ( 22/ 28 - x /2 )
. tan ( 22 - 14 x / 28 )
. sin / cos * 22 - 21 / 1 -sin
. cos + sin / 1 - sin²
. cos x / 1 - sin x * 1 + sin x /
. 1 + sin x
. thus cos x / 1 - sin x
. lhs