Having trouble understanding this integration

[Stochastic13]

I am reading through this physics book and have trouble understanding how they integrated one of the problems the conditions are

Conditions: // ignoring the constant for simplicity

r = √(x^2 + R^2)
sin(θ) = R/√(x^2 + R^2)

Integration:

∫ R/(x^2 + R^2)^3/2 dx

and the result is: x/R(x^2 + R^2)^1/2

Could someone please explain to me how the integration part was done in more detail?

 

[Stochastic13]

Nevermind, I had to use a substitution x = R tan (theta)