Public Domain Aeronautical Software (PDAS)  

The archive file quartic.zip contains the files:

readme.txt this file of general description
quartic.f90 the complete source code

This program computes the solution to the polynomial equation

a*x**4 + b*x**3 + c*x**2 + d*x + e = 0

with real coefficients.

The program asks for the coefficients of each term of the polynomial to be solved. If you are solving a cubic, answer zero to the question "What is the coefficient of the quartic term?"

Public Domain Aeronautical Software (PDAS)