Math

Descartes' Rule of Signs Calculator

Possible positive and negative real-root counts for a cubic.

Free to use — no sign-up or login.

Possible positive

Possible negative

This free Descartes' Rule of Signs Calculator covers Possible positive and negative real-root counts for a cubic.

Enter the Descartes' Rule of Signs Calculator fields, then read the output. Math calculators on this site keep the formula visible beside the form, with no account required.

Using the Descartes' Rule of Signs Calculator

Possible positive and negative real-root counts for a cubic. Typical inputs are a, b, c and d. How it works beside the form states the identity the Descartes' Rule of Signs Calculator applies.

FAQ

How do I use the Descartes' Rule of Signs Calculator?

Open the Descartes' Rule of Signs Calculator, fill a, b, c and d, and read the result. Sign changes in p(x) bound positive roots; sign changes in p(−x) bound negative roots.

What formula does the Descartes' Rule of Signs Calculator use?

The Descartes' Rule of Signs Calculator uses the identity in How it works. In words: Sign changes in p(x) bound positive roots; sign changes in p(−x) bound negative roots.