Here's the problem
limit (sqrt(x^2+5x)-x)
x->[infinity]
The answer is (according to two websites and my calculator) 5/2.
Here's the work I've done so far.
[Multiply the conjugate]
(sqrt(x^2+5x)-x)/1 * (sqrt(x^2+5x)+x)/(sqrt(x^2+5x)+x)
x^2+5x-x^2/(sqrt(x^2+5x)+x) = 5x/(sqrt(x^2+5x)+x)
and I don't know how to get farther than that. Please help!