# include <stdio.h>
# include <math.h>
/*****************************************************************/

void rtfunct(float x)
/* Given function f(x) = 0	*/
{
	extern float fx, dfx;


	switch(problem_id)
	{
		case 1:	/* Problem-1 */
				fx = 1+5.25*x-1/cos(sqrt(0.68*x));
				dfx = 5.25-(0.4123/sqrt(x))*sin(sqrt(0.68*x))/(cos(sqrt(0.68*x))*cos(sqrt(0.68*x)));
				break;

		case 2:	/* Problem-2 */
				fx = 1+x*x-8*x+16;
				dfx = 2*x-8;
				break;

		case 3:	/* Problem-3 */
				fx = x*x-8*x+16;
				dfx = 2*x-8;
				break;

		case 4:	/* Problem-4 */
				fx = x*x*x-5*x+1;
				dfx = 3*x*x-5;
				break;

		case 5:	/* Problem-5 */
				fx = cos(x)-x*exp(x);
				dfx = -sin(x)-exp(x)-x*exp(x);
				break;

		case 6:	/* Problem-6 */
				fx = sin(x);
				dfx = cos(x);
				break;

		case 7:	/* Problem-7 */
				fx = 1+sin(x);
				dfx = cos(x);
				break;

		case 8:	/* Problem-8 */
				fx = tan(x);
				dfx = 1/(cos(x)*cos(x));
				break;
	}

	return;
}
/*****************************************************************/