Question

please help...
find the derivative w.r.t X at X=π/2
(1-sinX)/(1+sinX)

Answer 1

${y}^{1 } = \frac{(1 + sinx)( - cosx) - (1 - sinx)cosx}{ {(1 + sinx)}^{2} }$
at
$x = \frac{\pi}{2}$
${y}^{1} = 0$