If $\begin{vmatrix}-a^2&ab&ac\\ba&-b^2&bc\\ac&bc&-c^2\end{vmatrix}=k.a^lb^mc^n$, then Match List-I with List-II
Choose the correct answer from the options given below: |
(A)-(IV), (B)-(II), (C)-(III), (D)-(I) (A)-(I), (B)-(III), (C)-(II), (D)-(IV) (A)-(II), (B)-(IV), (C)-(I), (D)-(III) (A)-(III), (B)-(I), (C)-(IV), (D)-(II) |
(A)-(III), (B)-(I), (C)-(IV), (D)-(II) |
The correct answer is Option (4) → (A)-(III), (B)-(I), (C)-(IV), (D)-(II)
Given: $\left|\begin{array}{ccc} -a^2 & ab & ac \\ ba & -b^2 & bc \\ ac & bc & -c^2 \end{array}\right| = k \cdot a^l b^m c^n$ Factor terms row-wise:
$abc \cdot \left|\begin{array}{ccc} -a & b & c \\ a & -b & c \\ a & b & -c \end{array}\right|$ Now evaluate the inner $3 \times 3$ determinant: Expand along first row: $= -a \cdot \left| \begin{array}{cc} -b & c \\ b & -c \end{array} \right| - b \cdot \left| \begin{array}{cc} a & c \\ a & -c \end{array} \right| + c \cdot \left| \begin{array}{cc} a & -b \\ a & b \end{array} \right|$ $= -a(0) - b(-2ac) + c(2ab) = 0 + 2abc + 2abc = 4abc$ Total determinant: $abc \cdot 4abc = 4a^2b^2c^2$ So: $k = 4$, $l = m = n = 2$ Now match List-I with List-II: (A) $l = m = n = 2$ ⟹ (A) → (III) (B) $k + l + m + n = 4 + 2 + 2 + 2 = 10$ ⟹ (B) → (I) (C) $k^2 + l^2 + (m - n)^2 = 4^2 + 2^2 + (2 - 2)^2 = 16 + 4 + 0 = 20$ ⟹ (C) → (IV) (D) $l^2 + m^2 + (n - k) = 2^2 + 2^2 + (2 - 4) = 4 + 4 - 2 = 6$ ⟹ (D)→ (II) |