Here ,
I=int1/(x^(5/2)(1+x^2)^(1/4))dxI=∫1x52(1+x2)14dx
Substitute color(red)(x=1/t=>dx=-1/t^2dtx=1t⇒dx=−1t2dt
So,
I=int1/((1/t)^(5/2)(1+1/t^2)^(1/4))(-1/t^2)dtI=∫1(1t)52(1+1t2)14(−1t2)dt
=-intt^(5/2)/((t^2+1)^(1/4)/t^(1/2))*1/t^2dt=−∫t52(t2+1)14t12⋅1t2dt
=-intt^(5/2+1/2-2)/(t^2+1)^(1/4)dt=−∫t52+12−2(t2+1)14dt
:.I=-intt/(t^2+1)^(1/4)dt
Substitute color(blue)((t^2+1)^(1/4)=u=>t^2+1=u^4
=>2tdt=4u^3du=>tdt=2u^3du
I=-int(2u^3)/udu
=>I=-2intu^2du
=>I=-2[u^3/3]+c
=-2/3(u)^3+c
Subst. back , color(blue)(u=(t^2+1)^(1/4)
I=-2/3(t^2+1)^(3/4)+c
Again subst. color(red)(t=1/x
:.I=-2/3(1/x^2+1)^(3/4)+c
=>I=-2/3(1+x^2)^(3/4)/(x^2)^(3/4)+c
:.I=-(2(1+x^2)^(3/4))/(3x^(3/2))+c