XLPack 6.1
Excel Worksheet Function Numerical Library Reference Manual
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◆ WCpqr792()

Function WCpqr792 ( N As  Long,
A As  Variant 
)

Roots of a polynomial (complex coefficients) by computing the eigenvalues of the companion matrix (complex numbers in pairs of cells)

Purpose
WCpqr792 computes all roots of a polynomial p(z) with complex coefficients by computing the eigenvalues of the companion matrix.
p(z) = a0*z^n + a1*z^(n-1) + ... + an

To represent complex numbers, a real part and an imaginary part are stored in a pair of adjacent cells (a real part in a left cell, and an imaginary part in a right cell). The computed results are stored in the same way.
Returns
N+1 x 2
Column 1Columns 2
Rows 1 to NReal parts of the rootsImaginary parts of the roots
Row N+1Return code0

Return code.
= 0: Successful exit.
= 1: Maximum number of iterations (30) exceeded.
Parameters
[in]NDegree of polynomial. (N >= 1)
[in]A(N+1 x 2) Complex coefficients a0 to an of polynomial a0 x^n + a1 x^(n-1) + … + a(n-1)x + an.
Reference
SLATEC
Example
Solve the following algebraic equation.
x^3 + (-19-14i)*x^2 + (67+191i)*x + 116-612i = 0
The exact solutions are 8 + 4i, 4 + 9i and 7 + i.

WCpqr792