公式法求解

解题思路:

注意事项:

参考代码:

#include <stdio.h>

#include <math.h>

int main(int argc, char *argv[]) {

float a,b,c;

scanf("%f%f%f",&a,&b,&c);

if(b*b-4*a*c>0)

printf("x1=%.3f x2=%.3f",(-b+sqrt(b*b-4*a*c))/2*a,(-b-sqrt(b*b-4*a*c))/2*a);

if(b*b-4*a*c==0)

printf("x1=%.3f,x2=%.3f",(-b+sqrt(b*b-4*a*c))/(2*a),(-b+sqrt(b*b-4*a*c))/(2*a));

if(b*b-4*a*c<0)

printf("x1=%.3f+%.3fi x1=%.3f-%.3fi",(-b)/(2*a),sqrt(fabs(b*b-4*a*c))/(2*a),(-b)/(2*a),sqrt(fabs(b*b-4*a*c))/(2*a));

return 0;

}