数值分析——二分法求方程的根（Python实现）

def Dic(a,b):
    fa=fun(a)
    fb=fun(b)
    while a<=b:
       mid=(a+b)/2
       fm=fun(mid)
       if abs(fm)<10e-9:
           print("方程的根为",mid)
           break
       if fa*fm<0:
           a=a
           b=mid
           fb=fun(b)
           print("解在[",a,",",b,"]之间")
       elif fb*fm<0:
           a=mid
           b=b
           fa=fun(a)
           print("解在[",a,",",b,"]之间")
    return mid
    
def fun(x):
    return pow(x,3)-x-1  #pow(x,3)表示x的3次幂
    
a=1
b=1.5
Dic(a,b)

例题来自：李庆扬《数值分析》第五版