float fredin(float x, int n, float a, float b, float t[], float f[],
	float w[], float (*g)(float), float (*ak)(float, float))
{
	int i;
	float sum=0.0;

	for (i=1;i<=n;i++) sum += (*ak)(x,t[i])*w[i]*f[i];
	return (*g)(x)+sum;
}