Second question

I am supposed to integrate this question by using trig substitution

Integrate

dx/(x^2 * (x^2 + 1) ^1/2)

So I made my triangle, (x^2 + 1) is the hypotenuse, x 1 is adjacent to theta, and x is oposite of theta. Theta = to one angle

So

Tan (theta) = x/1 so

x= tan(theta)

dx = sec^2 theta

sec (theta) = (x^2 + 1)^1/2

So for my substituted integral I get

(sec(theta))^2/[(tan(theta))^2(sec(theta))]

So I get the one sec(theta) to cancel and I am left with

(sec(theta))/[((tan(theta))^2]

i can't seem to integrate it from there. I tried different trig identies, but nothing is working out.

Thanks