{
TF1 *fa1 = new TF1("fa1","(1.0-1.0/(2.0-cos(x)))+(1.0-1.0/(2.0-cos(x)))*(1.0-1.0/(2.0-cos(x)))*(1.0-1.0/(2.0-cos(x)))-(1.0-1.0/(2.0-cos(x)))*(1.0-1.0/(2.0-cos(x)))*sin(x)*sin(x)",0,TMath::Pi());
fa1->Draw();

//Integral con Wolfram:
//integrate (1.0-1.0/(2.0-cos(x)))+(1.0-1.0/(2.0-cos(x)))*(1.0-1.0/(2.0-cos(x)))*(1.0-1.0/(2.0-cos(x)))-(1.0-1.0/(2.0-cos(x)))*(1.0-1.0/(2.0-cos(x)))*sin(x)*sin(x) dx from x=0 to pi
//https://www.wolframalpha.com/input/?i=integrate+%281.0-1.0%2F%282.0-cos%28x%29%29%29%2B%281.0-1.0%2F%282.0-cos%28x%29%29%29*%281.0-1.0%2F%282.0-cos%28x%29%29%29*%281.0-1.0%2F%282.0-cos%28x%29%29%29-%281.0-1.0%2F%282.0-cos%28x%29%29%29*%281.0-1.0%2F%282.0-cos%28x%29%29%29*sin%28x%29*sin%28x%29+dx+from+x%3D0+to+pi
//https://www.wolframalpha.com/input/?i=integrate+%281.0-1.0%2F%282.0-cos%28x%29%29%29%2B%281.0-1.0%2F%282.0-cos%28x%29%29%29*%281.0-1.0%2F%282.0-cos%28x%29%29%29*%281.0-1.0%2F%282.0-cos%28x%29%29%29-%281.0-1.0%2F%282.0-cos%28x%29%29%29*%281.0-1.0%2F%282.0-cos%28x%29%29%29*sin%28x%29*sin%28x%29+dx

TF1 *fa2 = new TF1("fa2","((1.0-1.0/(2.0-cos(x)))+(1.0-1.0/(2.0-cos(x)))*(1.0-1.0/(2.0-cos(x)))*(1.0-1.0/(2.0-cos(x)))-(1.0-1.0/(2.0-cos(x)))*(1.0-1.0/(2.0-cos(x)))*sin(x)*sin(x))/(1.37546)",0,TMath::Pi());
fa2->Draw();

TF1 *fa2 = new TF1("fa2","((1.0-1.0/(2.0-cos(x)))+(1.0-1.0/(2.0-cos(x)))*(1.0-1.0/(2.0-cos(x)))*(1.0-1.0/(2.0-cos(x)))-(1.0-1.0/(2.0-cos(x)))*(1.0-1.0/(2.0-cos(x)))*sin(x)*sin(x))/(1.37546)",0,TMath::Pi());
fa2->Draw();

//Hemos fijado que gamma=1 porque sólo tendremos en cuenta 2 interacciones.

}