Solution
Related Formula
For a quadratic equation Ax² + Bx + C = 0, roots can be obtained via the quadratic formula:
x = -B ± √(B² - 4AC)2ACore Logic
Given quadratic equation:
x²-(3-2i)x-(2i-2)=0Using the quadratic formula where A=1, B=-(3-2i), C=-(2i-2):
x = (3-2i) ± √((3-2i)² - 4(1)(-(2i-2)))2Step 1: Simplify the Discriminant
Discriminant D = (3-2i)² + 4(2i-2) D = (9 - 4 - 12i) + (8i - 8) D = 5 - 12i + 8i - 8 = -3 - 4iWe need to find √(-3-4i). Let it be written as a perfect square:
-3-4i = 1 - 4 - 4i = 1² + (2i)² - 2(1)(2i) = (1-2i)²Thus, √(D) = ±(1-2i).
Step 2: Find the Roots
Boxedx = ((3-2i) ± (1-2i))/(2)
Case 1 (+ sign):
x₁ = (3 - 2i + 1 - 2i)/(2) = (4 - 4i)/(2) = 2 - 2iCase 2 (- sign):
x₂ = (3 - 2i - 1 + 2i)/(2) = (2)/(2) = 1 + 0iLet the roots be α + iβ = 2 - 2i α=2, β=-2 and γ + iδ = 1 + 0i γ=1, δ=0
Step 3: Evaluate Target Expression
αγ + βδ = (2)(1) + (-2)(0) = 2Pattern Recognition
Always try to express the complex number under the square root in the form (a + bi)² by matching the imaginary part 2ab = -4i ab = -2, and a² - b² = -3. This avoids long calculations.
Chapter Mix
Class 11 Mathematics: Complex Numbers and Quadratic Equations