equation.c

/* To Solve Differential Equation */

#include <stdio.h>

#include <conio.h>

#include <math.h>

float poly(float a[], int, float);

float deriv(float a[], int, float);

int main()

{

    float x, a[10], y1, dy1;

    int deg, i;

    printf("Enter the degree of polynomial equation: ");

    scanf("%d", &deg);

    printf("Ehter the value of x for which the equation is to be evaluated: ");

    scanf("%f", &x);

    for (i = 0; i <= deg; i++) {

        printf("Enter the coefficient of x to the power %d: ", i);

        scanf("%f", &a[i]);

    }

    y1 = poly(a, deg, x);

    dy1 = deriv(a, deg, x);

    printf("The value of polynomial equation for the value of x = %.2f is: %.2f", x, y1);

    printf("\nThe value of the derivative of the polynomial equation at x = %.2f is: %.2f", x, dy1);

    return 0;

}

/* function for finding the value of polynomial at some value of x */

float poly(float a[], int deg, float x)

{

    float p;

    int i;

    p = a[deg];

    for (i = deg; i >= 1; i--) {

        p = (a[i - 1] + x * p);

    }

    return p;

}

/* function for finding the derivative at some value of x */

float deriv(float a[], int deg, float x)

{

    float d[10], pd = 0, ps;

    int i;

    for (i = 0; i <= deg; i++) {

        ps = pow(x, deg - (i + 1));

        d[i] = (deg - i) * a[deg - i] * ps;

        pd = pd + d[i];

    }

    return pd;

}