How to use the quadratic discriminant calculator
Find the discriminant of a quadratic equation and what it says about its roots. Enter coefficient a, coefficient b, constant c in the fields above; the discriminant d, root type are computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “discriminant”, “how many roots does quadratic have”, “b squared minus 4ac”, “calculate quadratic discriminant”, “find discriminant d”.
Formula
Variables
- a — Coefficient a
- b — Coefficient b
- c — Constant c
Worked example
With coefficient a = 1, coefficient b = 2, constant c = 5, the calculator gives discriminant d ≈ -16; root type ≈ Two complex roots text.
Frequently asked questions
What is the quadratic discriminant calculator used for?
Find the discriminant of a quadratic equation and what it says about its roots. It helps with questions such as “discriminant”, “how many roots does quadratic have”, “b squared minus 4ac”.
What is the formula for the quadratic discriminant calculation?
Discriminant D = b × b-4 × a × c. Root type (text) = [Discriminant D]>0?"Two distinct real roots":([Discriminant D]==0?"One repeated real root":"Two complex roots"). Here a is coefficient a, b is coefficient b, c is constant c.
What inputs do I need for the quadratic discriminant calculator?
You need coefficient a, coefficient b, constant c. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the quadratic discriminant calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the quadratic discriminant result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.