double dU = PI;
	double dL = 0.0;
	double b = dL;
	int nSteps = 100;
	double db = (dU-dL)/nSteps;
	double dF;
	double dFF;
	double dInteg = 0.0;
	for (int ii = 0; ii < nSteps; ii++)
	{
		if (ii == 0)
			dF = a * ( sin(2*b*x*sin(b)) * sin(2*b*x*sin(b)) ) * sin(b);
		else
			dF = dFF;
		b += db;
		dFF = a * ( sin(2*b*x*sin(b)) * sin(2*b*x*sin(b)) ) * sin(b);
		dInteg += 0.5*(dF + dFF)*db;
	}
	y = dInteg;