anonymous 5 years ago Can someone help me in u substitution i forgot how to do that.

1. anonymous

Yes

2. anonymous

Post a problem

3. anonymous

What's the problem?

4. anonymous

If the substitution $u=\sqrt{x-1}$ is made, the integral $\int\limits_{2}^{5} \sqrt{x-1}\div x dx=$

5. anonymous

u=$\sqrt{x-1}$

6. anonymous

so du= $1\div(2(\sqrt{x-1})$

7. anonymous

try it from there

8. anonymous

ok i've got that so far

9. anonymous

i need to find x too right?

10. anonymous

no because u is equal to that part of the denominator

11. anonymous

so you have, 2$2\int\limits_{}^{}u^2/(u^2+1)$

12. anonymous

ok i don't get how you got that.

13. anonymous
14. anonymous

go there but don't forget the domain of integration

15. anonymous

thanks