Cubic Equation Calculator
Solves cubic equations of the form ax^3 + bx^2 + cx + d = 0. Provides real and complex roots with step-by-step solution.
Published by:
isCalculator Editorial Team
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How to use this tool?
This calculator solves cubic equations of the form ax³ + bx² + cx + d = 0.
- Enter coefficients a, b, c, and d in the input fields. Use decimal numbers (e.g., -6, 2.5).
- Click "Calculate" to find all three roots.
- View results: Roots are displayed as real numbers (e.g., 1.000000) or complex numbers (e.g., 2.000000+1.732051i).
- Step-by-step breakdown shows the depressed cubic, p, q, discriminant, and final roots.
Note: Coefficient a cannot be zero. All coefficients must be real numbers. The calculator automatically handles one real root (discriminant > 0), repeated roots (Δ = 0), or three real roots (Δ < 0).
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Frequently Asked Questions
A cubic equation is a polynomial equation of degree three, generally written as ax^3 + bx^2 + cx + d = 0, where a ≠ 0.
A cubic equation always has three roots (real or complex), counted with multiplicity.
If the discriminant is negative, the equation has three distinct real roots. The calculator uses trigonometric method to find them.
