#include<stdio.h>
#include<math.h>
#include<stdlib.h>

int main()
{
double a,b,c,r,x0=-10,y0=10;
double x1,y1;
double min=999;
int nlter;
printf("输入abc的值：");
scanf_s("%lf %lf %lf",&a,&b,&c);
printf("输入学习率：");
scanf_s("%lf",&r);

for(nlter=0;nlter<30;nlter++)
{
x1=x0-(r*((2*a*x0)-b));
y1=(a*x0*x0)+(b*x0)+c;
x0=x1;
y0=y1;

}
printf("x=%lf,min=%lf\n",x0,y0);
system("pause");

}