Differentiate given problems w.r.t.x.
cot−1[√1+sin x+√1−sin x√1+sin x−√1−sin x],0<x<π2.
Let y = cot−1[√1+sin x=√1−sin x√1+sin x−√1−sin x],.
=[(sinx2+cosx2)+(cosx2−sinx2)(sinx2+cosx2)−(cosx2−sinx2)]
⎡⎢ ⎢⎣∵1+sin x=sin2x2+cos2x2+2sinx2.cosx2=(sinx2+cosx2)2and 1−sin x=sin2x2+cos2x2−2 sinx2cosx2=(cosx2−sinx2)2⎤⎥ ⎥⎦
=cot−1(2 cos(x/2)2 sin(x/2))=cot1(cot(x2))=x2⇒dydx=12
Ifπ2<X<π,then√1−sin x=sinx2−cosx2.