Solving for the roots of a cubic polynomial

[Namir]

As I mentioned before the original HP-45 key sequence that I translated into HP-41C code seem to have been meant to solve a cubic equation x^3+a*x^2+b*x+c =0, for typical cases where a, b, and c are not zero. You are welcome to enhance the HP-41C code for various combinations of zeros in these three parameters. You can download the HP-45 Application Book from Eric Rechlin's documents web pages and look at pages 74 and 75 to see the equations used and the keystroke sequence. An alternative to all this is to use Lin-Bairstow's algorithm that solves for real and complex roots of polynomials with real coefficients.