Cos2Tan−1SinCot−1x=
x2+1x2+2
x2−1x2+2
x2+1x2−2
x2−1x2+1
We have
Cot−1x=Sin−111+x2andTan−1x=Cos−111+x2
∴cos2tan-1sincot-1x=cos2tan-111+x2 =11+11+x222 =x2+1x2+2