Evaluate: ∫10u9+10uloge10u10+10u du
(1)
Ans. log(10u+u10)+C
Explanation
The given integral is ∫10u9+10uloge10u10+10u du
Let u10+10u=v
Differentiating both sides, we get
ddu(u10+10u)=dvdu
10u9+10uloge10=dvdu
(10u9+10uloge10)du=dv
Substitute v for u10+10u and dv for (10u9+10uloge10)du in the given integral.
∫10u9+10uloge10u10+10u du=∫dvv
=∫1v dv
=logv+C
=log(u10+10u)+C (∵ v=u10+10u)