import math

def quadratic_equation(a, b, c):

? ? y = b*b - 4*a*c

? ? if y < 0:

? ? ? ? return?

? ? else:

? ? ? ? x1 = (-b+math.sqr(y))/(2*a)

? ? ? ? x2 = (-b-math.sqr(y))/(2*a)

? ? ? ? return x1,x2

print quadratic_equation(2, 3, 0)

print quadratic_equation(1, -6, 5)

cmd顯示如下：

F:\PythonTest>python test.py

Traceback (most recent call last):

? File "test.py", line 12, in <module>

? ? print quadratic_equation(2,3,0)

? File "test.py", line 9, in quadratic_equation

? ? x1 = (-b+math.sqr(y))/(2*a)

AttributeError: 'module' object has no attribute 'sqr'