void chder(float a, float b, float c[], float cder[], int n){	int j;	float con;	cder[n-1]=0.0;	cder[n-2]=2*(n-1)*c[n-1];	for (j=n-3;j>=0;j--)		cder[j]=cder[j+2]+2*(j+1)*c[j+1];	con=2.0/(b-a);	for (j=0;j<n;j++)		cder[j] *= con;}