If the matrix $A=\begin{bmatrix}α&β&γ\\0&0&2\\3&-2&0\end{bmatrix}$ is a skew symmetric matrix, then the value of $(α+β+γ)^2$ is: |
4 16 9 36 |
9 |
The correct answer is Option (3) → 9 A matrix A is skew-symmetric if Aᵀ = -A, which implies: 1. Diagonal elements must be 0 → α = 0, a₂₂ = 0 ✔, a₃₃ = 0 ✔ 2. Off-diagonal elements satisfy aᵢⱼ = -aⱼᵢ Given matrix: A = $\begin{bmatrix} \alpha & \beta & \gamma \\ 0 & 0 & 2 \\ 3 & -2 & 0 \end{bmatrix}$ $a₁₃ = γ → a₃₁ = 3 → γ = -3$ $a₁₂ = β → a₂₁ = 0 → β = 0$ Diagonal: α = 0 Therefore, α + β + γ = 0 + 0 + (-3) = -3 $(\alpha + \beta + \gamma)^2 = (-3)^2 = 9$ |