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If |(a^(2),b^(2),c^(2)),((a+lamda)^(2)...

If
`|(a^(2),b^(2),c^(2)),((a+lamda)^(2),(b+lamda)^(2),(c+lamda)^(2)),((a-lamda)^(2),(b-lamda)^(2),(c-lamda)^(2))|=k lamda|(a^(2),b^(2),c^(2)),(a,b,c),(1,1,1)|`
`lamda!=0` then k is equal to

A

`4 lamda abc`

B

`-4 lamda abc`

C

`4lamda^(2)`

D

`-4 lamda^(2)`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the given determinant equation, we will follow a systematic approach to simplify the determinant and find the value of \( k \). ### Step-by-Step Solution: 1. **Write the Determinant**: We start with the determinant: \[ D = \begin{vmatrix} a^2 & b^2 & c^2 \\ (a + \lambda)^2 & (b + \lambda)^2 & (c + \lambda)^2 \\ (a - \lambda)^2 & (b - \lambda)^2 & (c - \lambda)^2 \end{vmatrix} \] 2. **Expand the Rows**: Expand the second and third rows: \[ (a + \lambda)^2 = a^2 + 2a\lambda + \lambda^2 \] \[ (a - \lambda)^2 = a^2 - 2a\lambda + \lambda^2 \] Thus, we rewrite the determinant: \[ D = \begin{vmatrix} a^2 & b^2 & c^2 \\ a^2 + 2a\lambda + \lambda^2 & b^2 + 2b\lambda + \lambda^2 & c^2 + 2c\lambda + \lambda^2 \\ a^2 - 2a\lambda + \lambda^2 & b^2 - 2b\lambda + \lambda^2 & c^2 - 2c\lambda + \lambda^2 \end{vmatrix} \] 3. **Row Operations**: Now, we perform row operations to simplify the determinant. We can subtract the first row from the second and third rows: \[ R_2 \rightarrow R_2 - R_1 \] \[ R_3 \rightarrow R_3 - R_1 \] This gives us: \[ D = \begin{vmatrix} a^2 & b^2 & c^2 \\ 2a\lambda + \lambda^2 & 2b\lambda + \lambda^2 & 2c\lambda + \lambda^2 \\ -2a\lambda + \lambda^2 & -2b\lambda + \lambda^2 & -2c\lambda + \lambda^2 \end{vmatrix} \] 4. **Factor Out Common Terms**: Notice that each term in the second and third rows can be factored: \[ D = \begin{vmatrix} a^2 & b^2 & c^2 \\ \lambda^2 + 2a\lambda & \lambda^2 + 2b\lambda & \lambda^2 + 2c\lambda \\ \lambda^2 - 2a\lambda & \lambda^2 - 2b\lambda & \lambda^2 - 2c\lambda \end{vmatrix} \] 5. **Further Simplification**: We can express the determinant in terms of \( \lambda \): \[ D = \lambda^2 \begin{vmatrix} a^2 & b^2 & c^2 \\ 2a & 2b & 2c \\ -2a & -2b & -2c \end{vmatrix} \] 6. **Calculate the Determinant**: The determinant simplifies to: \[ D = 4\lambda^2 \begin{vmatrix} a^2 & b^2 & c^2 \\ a & b & c \\ 1 & 1 & 1 \end{vmatrix} \] 7. **Set Equal to Given Expression**: According to the problem statement: \[ D = k\lambda \begin{vmatrix} a^2 & b^2 & c^2 \\ a & b & c \\ 1 & 1 & 1 \end{vmatrix} \] Thus, we have: \[ 4\lambda^2 \begin{vmatrix} a^2 & b^2 & c^2 \\ a & b & c \\ 1 & 1 & 1 \end{vmatrix} = k\lambda \begin{vmatrix} a^2 & b^2 & c^2 \\ a & b & c \\ 1 & 1 & 1 \end{vmatrix} \] 8. **Divide Both Sides**: Since \( \lambda \neq 0 \), we can divide both sides by \( \lambda \): \[ 4\lambda \begin{vmatrix} a^2 & b^2 & c^2 \\ a & b & c \\ 1 & 1 & 1 \end{vmatrix} = k \begin{vmatrix} a^2 & b^2 & c^2 \\ a & b & c \\ 1 & 1 & 1 \end{vmatrix} \] 9. **Final Comparison**: By comparing coefficients, we find: \[ k = 4\lambda \] ### Conclusion: Thus, the value of \( k \) is \( 4 \).
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