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Question #40511

Difficulty: 8/10 | 🟢 Free

The Question

Let z1,z2,z3z_1, z_2, z_3 be the distinct complex roots of the equation z3=8z^3 = 8. Let A=(tt2−31t−4)A = \begin{pmatrix} t & t^2-3 \\ 1 & t-4 \end{pmatrix} be a transformation matrix, where t∈Zt \in \mathbb{Z}. For each k∈{1,2,3}k \in \{1, 2, 3\}, let wk=xk+iykw_k = x_k + i y_k be the complex number defined by the matrix multiplication (xkyk)=A(Re(zk)Im(zk))\begin{pmatrix} x_k \\ y_k \end{pmatrix} = A \begin{pmatrix} \text{Re}(z_k) \\ \text{Im}(z_k) \end{pmatrix} Consider the vectors v⃗k=(xk2yk21)\vec{v}_k = \begin{pmatrix} x_k^2 \\ y_k^2 \\ 1 \end{pmatrix} in R3\mathbb{R}^3. Given that the vectors v⃗1,v⃗2,v⃗3\vec{v}_1, \vec{v}_2, \vec{v}_3 are linearly dependent and the points w1,w2,w3w_1, w_2, w_3 are not collinear, let Δ\Delta be the area of the triangle formed by w1,w2,w3w_1, w_2, w_3 in the complex plane. Find the value of Δ2\Delta^2.

Options

  • A.

    675

  • B.

    225

  • C.

    135

  • D.

    507

Check Your Answer

Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Monster

Ultra-high difficulty questions designed to test your limit, stamina, and deep conceptual understanding.

Concepts Behind This Question

Geometry of Complex Inequalities|Linear Independence vs Dependence|Orthogonal Matrix Conditions

Why This Question Is Tricky

Common Mistakes

This question tests the geometric interpretation of linear dependence and matrix transformations.

The primary trap is attempting a brute-force expansion of the 3×33 \times 3 determinant of v⃗k\vec{v}_k, which leads to an intractable trigonometric polynomial.

The elegant solution requires recognizing that linear dependence of (x2,y2,1)(x^2, y^2, 1) implies the transformed points lie on an axis-aligned ellipse.

This directly translates to the condition that the transformation matrix AA must have orthogonal rows (i.e., AATA A^T is diagonal).

This beautifully connects linear algebra with coordinate geometry, forcing students to abandon pure algebra for geometric insight.

Quick Facts About This Question

Question Information

SubjectMathematics
ChapterComplex Numbers and Quadratic Equations - Class 11
ConceptGeometry of Complex Inequalities
Difficulty8
Cognitive Load7
Target Solve Time160 sec
AccessFree