Function: find the root of the equation by Newton iterative method

requirement

Find the root of the equation by Newton iterative method . The equation is ax3+bx2+cx+d=0, The coefficient is entered by the user , seek x stay 1 Nearby roots .
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Code

#include<math.h>
#define EPSILON 1E-6
/* *  function f(x)=a*x**3+b*x**2+c*x+d */
double f(double a,double b,double c, double d, double x)
{
    
    double t;
    t=a*x*x*x+b*x*x+c*x+d;
    return t;
}
/* *  function f(x)=a*x**3+b*x**2+c*x+d The derivative of  */
double derivatives(double a,double b,double c, double d, double x)
{
    
    double t;
    t=3*a*x*x+2*b*x+c;
    return t;
}
/* *  In this function, the equation is solved by iterative method in 1 Nearby roots , You can call the above f Functions and f The derivative of  */
double fun(double a,double b,double c,double d)
{
    
    double x1,x=1;
    do
    {
    
        x1=x;
    x = x1 - f(a,b,c,d,x)/derivatives(a,b,c,d,x);
    }
    while(fabs(x1-x)>=1e-3);
    return x;
 } 

test

Test input
10 5 -11 -3.28351

Output
Where is the equation 1 The root nearby is 0.97