求二次方程

Question

我的程序似乎没有给我正确的解决方案.有时确实如此,有时却没有.我找不到我的错误.有什么建议？

import math

a,b,c = input("Enter the coefficients of a, b and c separated by commas: ")

d = b**2-4*a*c # discriminant

if d < 0:
    print "This equation has no real solution"
elif d == 0:
    x = (-b+math.sqrt(b**2-4*a*c))/2*a
    print "This equation has one solutions: ", x
else:
    x1 = (-b+math.sqrt(b**2-4*a*c))/2*a
    x2 = (-b-math.sqrt(b**2-4*a*c))/2*a
    print "This equation has two solutions: ", x1, " and", x2

Answer 1

这条线导致了问题:

(-b+math.sqrt(b**2-4*a*c))/2*a

x/2*a被解释为(x/2)*a.你需要更多的括号:

(-b + math.sqrt(b**2 - 4*a*c)) / (2 * a)

此外,如果您已经存储d,为什么不使用它？

x = (-b + math.sqrt(d)) / (2 * a)

Answer 2

在这里,你应该每次都给你正确的答案!

a = int(input("Enter the coefficients of a: "))
b = int(input("Enter the coefficients of b: "))
c = int(input("Enter the coefficients of c: "))

d = b**2-4*a*c # discriminant

if d < 0:
    print ("This equation has no real solution")
elif d == 0:
    x = (-b+math.sqrt(b**2-4*a*c))/2*a
    print ("This equation has one solutions: "), x
else:
    x1 = (-b+math.sqrt((b**2)-(4*(a*c))))/(2*a)
    x2 = (-b-math.sqrt((b**2)-(4*(a*c))))/(2*a)
    print ("This equation has two solutions: ", x1, " or", x2)