Polynomial roots explorer calculator

Calculate complex roots as real, imaginary pairs and root count including multiplicity with your own figures.

Your numbers

Use the units shown. Results update as you change valid inputs.

Use complex roots as real, imaginary pairs and root count including multiplicity to compare changes to your inputs. The method and limits below explain the scope.

Examples

Examples

Try the starting example

Polynomial coefficients, highest degree first
1,-6,11,-6
Relative residual acceptance target
1e-08
Complex roots as real, imaginary pairs
1, 0; 2, 0; 3, 0
Root count including multiplicity
3
Maximum scaled polynomial residual
0
Residual check
Residual target met

Try another scenario

Polynomial coefficients, highest degree first
1,0,1
Relative residual acceptance target
1e-08
Complex roots as real, imaginary pairs
0, -1; 0, 1
Root count including multiplicity
2
Maximum scaled polynomial residual
0
Residual check
Residual target met
Calculation method

Calculation method

Complex roots as real, imaginary pairs

Build the monic companion matrix and obtain its real/complex eigenvalues. Degree is limited to 1–12.

Root count including multiplicity

Return one eigenvalue per polynomial degree, retaining multiplicity.

Maximum scaled polynomial residual

For each root divide |P(root)| by the coefficient-magnitude Horner scale at |root|; report the maximum.

Residual check

Compare the computed scaled residual with the supplied target; a residual is not a forward-error bound.

Symbols and units
a
Polynomial coefficients, highest degree first
b
Relative residual acceptance target

Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.

Assumptions & limits

Assumptions & limits

  • Real coefficient polynomials of degree 1–12, with a nonzero leading coefficient. Multiple or badly conditioned roots can be inaccurate despite small residuals. Double-precision results are approximate. Numeric tables use 12 significant digits and display components at roundoff scale (32 machine epsilons relative to their row or relevant calculation scale) as zero; scalar diagnostics retain full precision.
Are these inputs private?

These calculations run in your browser. A shared link contains the values you choose to share. Only questions submitted to the separate AI finder are sent to OpenAI.

Further reading

ml-matrix: numerical decompositions ↗

Background reading; this does not imply endorsement or independent review of SumFizz.

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