STATUS: Draft


Solving Polynomial Equations (6)

Create the needed variables

Let g1 be an object from Solving Polynomial Equations (5).

Introduction

So far cases up to a cubic degree have been examined. Conjecture 1 in Solving Polynomial Equations (5) describes the relationship between $c_0, c_1, c_2$ and $c_3$ and claimed that this relationship can explain the the value of the coefficent. Note that this has not explain the choice the sign of the term however but the sign can be explained by the following conjecture.

Conjecture 2

Any value of the coefficient can be generated by:

$$(-1)^{c + 1} \frac{(k - 1)!}{a!b!c!}$$

where $a, b, c$ and $k$ are following values from any term in a solution for x in terms of $c_0, c_1, c_2$ and $c_3$:

$$\frac{c_0^a c_2^b c_3^c}{c_1^k}$$

Test this on the available data. Let g8 be g7 as a polynomial

The quartic case

Goal: Check if this holds in the quartic case. Assume that any values above $t^8$ are 0

Let g1 be a general quartic equation

Let g2 be a power series in $t$.

Let g4 be a g3 with a subsitution of x for g1 and a substitution of $t$ for $c_0$.

Let g5 be the expanion of g4. Recall that $t^8 = 0$ and let g6 be g5 with a subsitution of $t^8 = 0$

Let g7 be the value of of g6 evaluated where $t=0$

Let g8 be the factorisation of g7

Note there are multiple solutions to g8 and one of these is 0. Assume the case where $a_0 = 0$

Iteratively solve this for values of $a_0$ through $a_8$.

Visualise the results of solutions of $a_0$ through $a_8$

Substitute values $a_0$ through $a_8$ back into general quartic

$$ \left(a_{0} + a_{1} t + a_{2} t^{2} + a_{3} t^{3} + a_{4} t^{4} + a_{5} t^{5} + a_{6} t^{6} + a_{7} t^{7} + a_{8} t^{8}\right) + c_{2} \left(a_{0} + a_{1} t + a_{2} t^{2} + a_{3} t^{3} + a_{4} t^{4} + a_{5} t^{5} + a_{6} t^{6} + a_{7} t^{7} + a_{8} t^{8}\right)^{2} + c_{3} \left(a_{0} + a_{1} t + a_{2} t^{2} + a_{3} t^{3} + a_{4} t^{4} + a_{5} t^{5} + a_{6} t^{6} + a_{7} t^{7} + a_{8} t^{8}\right)^{3} + c_{4} \left(a_{0} + a_{1} t + a_{2} t^{2} + a_{3} t^{3} + a_{4} t^{4} + a_{5} t^{5} + a_{6} t^{6} + a_{7} t^{7} + a_{8} t^{8}\right)^{4} + t = 0 $$

Subsitute $c_0$ for t

Convert g14 into a Poly type and check that conjecture 2 holds.

Conjecture 3

The pattern still holds, note there is another variable, $c_4$. The conjecture can be extended to

$$(-1)^{c + 1} \frac{(k - 1)!}{a!b!c!d!}$$

where $a, b, c, d$ and $k$ are following values from any term in a solution for x in terms of $c_0, c_1, c_2, c_3$ and $c_4$:

$$\frac{c_0^a c_2^b c_3^c c_4^d}{c_1^k}$$

Create a function for this conjecture and test it against the data

Summary

The data still still holds. This means that for these values, these are solutions that can be generate and the terms in the original equations can be used to ascertain roots in these cases. The conjectures suggest a more general solution, related to larger power of t and larger powers of general polynomials