Python Math: Find the roots of a quadratic function

Last update on April 24 2025 12:35:14 (UTC/GMT +8 hours)

30. Quadratic Roots Finder

Write a Python program to find the roots of a quadratic function.

Sample Solution:

Python Code:

from math import sqrt

print("Quadratic function : (a * x^2) + b*x + c")
a = float(input("a: "))
b = float(input("b: "))
c = float(input("c: "))

r = b**2 - 4*a*c

if r > 0:
    num_roots = 2
    x1 = (((-b) + sqrt(r))/(2*a))     
    x2 = (((-b) - sqrt(r))/(2*a))
    print("There are 2 roots: %f and %f" % (x1, x2))
elif r == 0:
    num_roots = 1
    x = (-b) / 2*a
    print("There is one root: ", x)
else:
    num_roots = 0
    print("No roots, discriminant < 0.")
    exit()

Sample Output:

Quadratic function : (a * x^2) + b*x + c                                                                      
a: 5                                                                                                          
b: 20                                                                                                         
c: 10                                                                                                         
There are 2 roots: -0.585786 and -3.414214

Flowchart:

$Flowchart: Find the roots of a quadratic function$

For more Practice: Solve these Related Problems:

Write a Python program that calculates the roots of a quadratic equation using the quadratic formula, and prints both roots formatted to 6 decimal places.
Write a Python function that takes coefficients a, b, and c, computes the roots (real or complex), and returns them as a tuple.
Write a Python script to prompt the user for quadratic coefficients, then output the nature of the roots (real and distinct, real and equal, or complex) along with the computed values.
Write a Python program to compare the roots of two quadratic equations and print which one has the larger positive root.

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Python Code Editor:

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