Sure! Here are some important questions from the chapter "Complex Numbers and Quadratic Equations" that are relevant for Class 11 students following the NCERT curriculum:
Complex Numbers
- Definition: What are complex numbers? Define a complex number in the standard form \( z = a + bi \).
- Imaginary Unit: What is the value of \( i \) and how is it defined?
- Addition and Subtraction: If \( z_1 = 3 + 4i \) and \( z_2 = 1 - 2i \), calculate \( z_1 + z_2 \) and \( z_1 - z_2 \).
- Multiplication: Multiply \( z_1 = 2 + 3i \) and \( z_2 = 4 + i \). Express the result in standard form.
- Modulus: Find the modulus of the complex number \( z = 3 - 4i \).
- Conjugate: What is the conjugate of a complex number? Find the conjugate of \( z = 5 + 6i \).
- Division: Divide \( z_1 = 4 + 3i \) by \( z_2 = 1 - i \) and express in standard form.
- Polar Form: Convert the complex number \( z = 1 + \sqrt{3}i \) into polar form.
- De Moivre's Theorem: State De Moivre’s theorem and use it to find \( (2(\cos 30^\circ + i\sin30^\circ))^3 \).
- Roots of Unity: Find the cube roots of unity.
Quadratic Equations
- Standard Form: Write the general form of a quadratic equation. Give examples.
- Roots Formula: State and derive the quadratic formula for the roots of \( ax^2 + bx + c = 0 \).
- Nature of Roots: Using the discriminant \( D \), explain how to determine whether the roots are real and distinct, real and equal, or complex.
- Example Calculation: Find the roots of the quadratic equation \( x^2 - 5x + 6 = 0 \).
- Sum and Product: For the quadratic equation \( ax^2 + bx + c = 0 \), express the sum and product of the roots in terms of \( a, b, \) and \( c \).
- Graphical Representation: Sketch the graph of a quadratic equation and indicate the roots.
- Applications: Solve a word problem that involves formulating and solving a quadratic equation.
- Factoring: Factor the quadratic \( x^2 - 7x + 10 \) and find its roots.
- Vertex Form: Convert the quadratic equation \( y = 2x^2 - 8x + 6 \) into vertex form.
- Real-life Applications: Provide a real-life scenario where quadratic equations can be applied (e.g., projectile motion).
These questions cover a range of fundamental concepts in complex numbers and quadratic equations that are significant for exam preparation. Make sure to practice solving these problems, as well as understanding the underlying theories.