Quadratic Equations: Negative Discriminants, Complex Root Pairs and Checking by Substitution
This lesson is part of the course
In this lesson
You classify six quadratic equations by their discriminant, compute the centre and spread of their roots, and prove one complex root correct by putting it back into the equation.
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Lessons in this course
- The Complex Plane: Real & Imaginary Columns, Quadrants and Conjugates Locked
- Complex Arithmetic: Sums, Products (ac − bd, ad + bc) and Division by the Conjugate Locked
- Modulus & Argument: Distances, ATAN with a Quadrant Correction, Degrees vs Radians Locked
- Polar Form: r(cos θ + i sin θ), Multiplying Moduli and Adding Angles Locked
- Powers & Roots: De Moivre's Rule, n-th Roots and the Roots of Unity Locked
- Rotations & Scaling: Multiplying a Shape by a Complex Number Locked
- Quadratic Equations: Negative Discriminants, Complex Root Pairs and Checking by Substitution Locked
- AC Phasors: Impedance R + jX in Series and Parallel, Current Magnitude and Phase Angle Locked