用C语言编写,不准用系统函数哦
用牛代法求X的三分一次方
- 提问者网友:美人如花
- 2021-04-27 23:01
- 二级知识专家网友:安稳不如野
- 2021-04-28 00:30
这里举例求3的立方根,并取2为迭代初值计算。你可以去其他迭代初值。
#include<stdio.h>
#include<math.h>
#include "stdlib.h"
#include<conio.h>
#define N 100
#define PS 1e-5
#define TA 1e-5
float C;
void main()
{
float Newton(float (*f)(float),float(*f1)(float),float x0 );
float f(float);
float f1(float);
float x0,y0;
printf("Input num to caculate:");
scanf("%f",&C);
printf("Input first x0: ");
scanf("%f",&x0);
printf("x(0)=%f\n",x0);
y0=Newton(f,f1,x0);
printf("\nThe root is x=%f\n",y0);
}
float Newton(float (*f)(float),float(*f1)(float),float x0 )
{ float x1,d=0;
int k=0;
do
{ x1= x0-f(x0)/f1(x0);
if((k++>N)||(fabs(f1(x1))<PS))
{ printf("\nFailed!");
exit(0);
}
d=(fabs(x1)<1?x1-x0:(x1-x0)/x1);
x0=x1;
printf("x(%d)=%f\n",k,x0);
}
while((fabs(d))>PS&&fabs(f(x1))>TA) ;
return x1;
}
float f(float x)
{ return x*x*x-C; }
float f1(float x)
{ return 3*x*x; }