Cambridge IGCSE Additional Mathematics · Syllabus 0606 · Quadratic Functions
Quadratic Inequality
What is Quadratic Inequality?
An inequality in which a quadratic expression is compared with zero, such as ax^2 + bx + c less than or equal to zero. Its answer is a solution set, not a pair of numbers: the set of all x for which the statement is true. The roots of the corresponding equation are the critical values where the expression changes sign, and the opening direction of the parabola then decides whether the wanted region lies between those roots or outside them. Endpoints belong to the set only when the inequality is non-strict.
This definition is part of the Quadratic Functions chapter in Cambridge IGCSE Additional Mathematics.