Cubic Inequality Solver

Solve a cubic inequality ax³+bx²+cx+d against 0 and see the solution as intervals on a number line.

Input

Enter coefficients a, b, c, d and an inequality sign to solve the cubic inequality.

a x³ + b x² + c x + d > 0

Coefficient a

Coefficient b

Coefficient c

Coefficient d

Inequality sign

Solution range

above 1 and below 2 or x greater than 3

Number line

Number of real roots

Real roots

1 , 2 , 3

List of real roots

The cubic ax³+bx²+cx+d is solved numerically to find its real roots, which are listed in ascending order.
The real roots split the number line into intervals, and the sign of the cubic is checked at a sample point inside each interval.
Intervals that satisfy the chosen inequality are joined to form the solution. For non strict signs the roots themselves are included.
When the coefficient a is 0 the tool treats the input as a quadratic or linear inequality.

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