### integrating with unspecified constants

in the online sage I typed:
var('x,a,b')
integrate(1/sqrt(b+a/x), x)

And it answered:
Traceback (click to the left of this block for traceback)
...
Is b positive or negative?

Of course b is positive but there is no way to answer it's question or to predefine b as positive, so far as I know.
so I used b^2 and got a question "Is b > 0?". Well yes b>0. So is a.

a and b are part of a physics problem. They change with the initial conditions.
This is my first day with Sage. I have no idea what trace back is good for.

I don't know how to use this thing so send a copy of the answer to me at august04@frontier.com.