Bracketed Polynomial Root Finder

How to use Bracketed Polynomial Root Finder

A polynomial is continuous. Exact rational Horner signs for the parsed binary bracket points guide bisection; a genuine sign change encloses at least one root. Endpoint or exact midpoint roots return directly, while other outcomes retain a bounded enclosure.

1. Enter coefficients, constant first, lower bracket point, upper bracket point, absolute enclosure width tolerance.
2. Choose the stated convention and check the units and supported model.
3. Calculate, inspect the result, then copy or download it.

Good to know

• Degree1–20plain-decimal coefficients, bracket within±1million, absolute tolerance1e-12–1 and at most200steps. Not all roots, a symbolic solution or an even-root detection scan. Unresolvable brackets/bit budgets reject.
• Runs locally. Text/JSON fields are capped at30,000 characters; stricter page-specific and numeric-string limits also apply. Numeric inputs are bounded to magnitude1e15 and nonzero magnitude at least1e-100 unless an exact-string mode states otherwise. Approximate summaries use12 significant digits; CSV numeric cells retain the complete stored value and potentially formula-like string cells gain a protective apostrophe; unsupported, non-finite or detected underflow states return an error.