Hi all,(adsbygoogle = window.adsbygoogle || []).push({});

I am looking for a special case solution to the quartic equation x^4 + a x^3 + b x^2 + c x + d = 0 in the case where x = Cos[theta]. Are there are any special properties of the solutions? For example, I know there are numerous properties from Vieta's formula but none of these really help simplify things if x=cosine.

Natski

**Physics Forums - The Fusion of Science and Community**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Quartic eqn solutions for Cos/Sin

Loading...

Similar Threads - Quartic solutions | Date |
---|---|

I A nonlinear equation system | Mar 20, 2016 |

Root quartic | Apr 14, 2014 |

Solution to Quartic Equation with small first coefficient | May 22, 2013 |

When does quartic have only one real solution? | Jul 6, 2010 |

Analytical solutions of cubic and quartic equations | Apr 30, 2006 |

**Physics Forums - The Fusion of Science and Community**