Answer:
The simplest polynomial function is [tex]y = x^{4}-(7+\sqrt{13})\cdot x^{3}+(27+7\sqrt{13})\cdot x^{2}-(189+27\sqrt{13})\cdot x + 189\sqrt{13}[/tex].
Step-by-step explanation:
A n-th order polynomial in factorized form is defined by:
[tex]y = (x-r_{1})\cdot (x-r_{2})\cdot ...\cdot (x-r_{n-1})\cdot (x-r_{n})[/tex] (1)
Where:
[tex]x[/tex] - Independent variable.
[tex]y[/tex] - Dependent variable.
[tex]r_{1}[/tex], [tex]r_{2}[/tex],..., [tex]r_{n-1}[/tex], [tex]r_{n}[/tex] - Roots of the polynomial.
We know that three roots, two real and a complex root. By Quadratic Formula, a second order polynomial has two conjugated complex number of the form [tex]a + i\,b[/tex] and [tex]a - i\,b[/tex]. Hence, there is an additional zero: [tex]-i\,27[/tex].
By applying (1), we have the following polynomial when all roots are used:
[tex]y = (x-7)\cdot (x-\sqrt{13})\cdot (x-i\,27)\cdot (x+i\,27)[/tex]
By factorization and algebraic handling we have the simplest polynomial function:
[tex]y = [x^{2}-(7+\sqrt{13})\cdot x +7\sqrt{13}]\cdot (x^{2}+27)[/tex]
[tex]y = x^{2}\cdot (x^{2}+27)-(7+\sqrt{13})\cdot [(x^{2}+27)]\cdot x+7\sqrt{13}\cdot (x^{2}+27)[/tex]
[tex]y = x^{4}+27\cdot x^{2}-(7+\sqrt{13})\cdot x^{3}-(7+\sqrt{13})\cdot 27\cdot x +7\sqrt{13}\cdot x^{2}+189\sqrt{13}[/tex]
[tex]y = x^{4}-(7+\sqrt{13})\cdot x^{3}+(27+7\sqrt{13})\cdot x^{2}-(189+27\sqrt{13})\cdot x + 189\sqrt{13}[/tex]
The simplest polynomial function is [tex]y = x^{4}-(7+\sqrt{13})\cdot x^{3}+(27+7\sqrt{13})\cdot x^{2}-(189+27\sqrt{13})\cdot x + 189\sqrt{13}[/tex].
