Solving For Antiderivative

[Chris686]

Running through my homework fairly quickly, but now I'm stumped on how to solve this guy:

I'm not really sure where to begin on this guy. Can someone just do the first step or two? I'm thinking something like:

u = 5/x

But I'm not really sure, as my book doesn't have any fractions like this as examples.

 

[HallsofIvy]

Running through my homework fairly quickly, but now I'm stumped on how to solve this guy:

I'm not really sure where to begin on this guy. Can someone just do the first step or two? I'm thinking something like:

u = 5/x

But I'm not really sure, as my book doesn't have any fractions like this as examples.

So you want to integrate \(\displaystyle \int\frac{sin(\frac{5}{x}}{x^2} dx\).
Don't just think about it, do it! If \(\displaystyle u= \frac{5}{x}\) what is du?