Lesson 5 of 15Article18 min
Ch 4 — Complex Numbers and Quadratic Equations
i² = −1. Write z = a + bi; use conjugates, modulus, and the Argand plane. Quadratics with negative discriminant have complex roots.
Extending the number system
i² = −1. Write z = a + bi; use conjugates, modulus, and the Argand plane. Quadratics with negative discriminant have complex roots.
- Argand plane: real axis horizontal, imaginary vertical.
- Non-real roots of real-coefficient polynomials come in conjugate pairs.
Read this alongside the official NCERT chapter: Complex Numbers and Quadratic Equations — https://ncert.nic.in/textbook.php?kemh1=4-16 (full book index: https://ncert.nic.in/textbook.php?kemh1=0-16).