At the moment I'm trying to solve this integration problem and it's not working out asd neatly as any other substituion problem I've tried before. We have to integrate sqrtx divided by (1 + x^2) using the substitution x= tan^2t (as in tan squared t). So when we have dx/dt so you get 2tantsec^2t? I've tried using that but it all gets really muddled and complex. At the moment I'm down to finding the integral of 8 divided by -sin^2t but I'm not sue where to go from there. I've tried using substituions from this point on using the dpuble angle formulae but it's all going a bit pear-shaped. Any help would be much appreciated- thanks in advance!