Find the integrals of the functions.
∫cosx−sinx1+sin2xdx.
∫cosx−sinx1+sin2xdx.
Let I=∫cosx−sinx1+sin2xdx=∫cosx−sinxsin2x+cos2x+2sinx cosxdx
[∵sin2x+cos2x=1.sin2x=2sinx cosx]=∫cosx−sinx(sinx+cosx)2dxLet cosx+sinx=t⇒−sinx+cosx=dtdx⇒dx=dt(cosx−sinx)∴I=∫cosx−sinxt2.dt(cosx−sinx)=∫1t2=∫t−2dt=t−2+1−2+1+C=−1cosx+sinx+C