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Quadratic
| Question | |
|---|---|
| Quadratic formula | x = (−b ± √(b² − 4ac)) / 2a |
| Discriminant | D = b² − 4ac |
| If D > 0 | Roots are real and unequal |
| If D = 0 | Roots are real and equal |
| If D < 0 | Roots are complex and conjugate |
| Sum of roots (α + β) | −b / a |
| Product of roots (αβ) | c / a |
| Quadratic equation from roots α and β | x² − (α + β)x + αβ = 0 |
| If roots are reciprocal | c = a |
| Vertex of parabola | x = −b / (2a) |
| Maximum value of the quadratic expression | = f(−b / 2a) |
| What are the conditions for both roots to be greater than a number k? | The three conditions are: 1. D ≥ 0, 2. -b/2a > k, and 3. a × f(k) > 0. |
| What are the conditions for both roots to be less than a number k? | : The three conditions are: 1. D ≥ 0, 2. -b/2a < k, and 3. a × f(k) > 0 |
| What is the condition for a number k to lie between the two roots? | The single condition is a × f(k) < 0 |
| What are the conditions for both roots to lie between two numbers k₁ and k₂? | The three conditions are: 1. D ≥ 0, 2. k₁ < -b/2a < k₂, and 3. a × f(k₁) > 0 and a × f(k₂) > 0. |
| What is the condition for exactly one root to lie between two numbers k₁ and k₂? | The single condition is f(k₁) × f(k₂) < 0 |
| general cubic Sum of roots α+β+γ | =-b/a |
| Sum of products of roots (taken two at a time) αβ+βγ+γα | = c/a |
| Product of roots αβγ | = d/a |
| absolute difference between its two roots |x1 - x2| is given by | |x₁ - x₂| = b^2 - 4ac / |a| |
| If roots of a quadratic equations are rational then discriminant must be a? | perfect square |
| If a quadratic is greater than zero than is discriminant ? | less than zero |
| If a quadratic is greater than and equal to zero than is discriminant ? | less than or equal to zero |
| Minimum value of a Quadratic equation | -D/4a |