Integrate the following functions.
∫√tanxsinx.cosxdx.
∫√tanxsinx.cosxdx=∫√tanxsinxcosx×cosxcosxdx
[Multiply by 1=cosxcosx in denominator]
=∫√tanxtanx.cos2xdx=∫√tanxtanx.sec2xdx
Let tanx=t⇒sec2x=dtdx⇒dx=dtsec2x
∴∫√tanxtanx.sec2xdx=∫√tt.sec2xdtsec2x=∫1√tdt=∫t−12dt=t−12+1(−12+1)+C=2√t+C=2√tanx+C