Intergals, help

[cheshire_bitten]

hi guys I am a third year math student, and one of the classes I am taking this semester is scientific computing, we have an integral sin(x)/(1+x^2)^2 which is integrated from one to infinity, which we are meant to solve numerically using matlab, now the matlab is no problem, however I am meant to transform it into a finite interval by using

Comments

[elengul]

Well, using that substitution, look at your new bounds of integration. What does u equal when x is zero? What does u equal when x has gone off to infinity?

[cheshire_bitten]

I am probably misunderstanding you, but my problem is making the substitution, I know that if I could do that I would be fine, but don't I need a 2x on the top so that I can make the substitution

[madcaptenor]

I haven't actually done the problem. But the point here is not to get an integral that you can do analytically; rather it's to get an integrand on a finite interval that's sufficiently well-behaved that you can do it numerically.

[cheshire_bitten]

Yes, but I am getting stuck with f(g(x)) without any g'(x) where as all of the examples I can find are of the form f(g(x))g'(x), that is the derivative of F(g(x))