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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

`4lamda abc`

B

`-4lamda abc`

C

`4lamda^(2)`

D

`-4lamda^(2)`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the given determinant equation, we will follow these steps: ### Step 1: Write the Determinant We start with the determinant: \[ D = \begin{vmatrix} a^2 & b^2 & c^2 \\ (a + \lambda)^2 & (b + \lambda)^2 & (c + \lambda)^2 \\ (a - \lambda)^2 & (b - \lambda)^2 & (c - \lambda)^2 \end{vmatrix} \] ### Step 2: Expand the Second and Third Rows We expand the second and third rows: \[ (a + \lambda)^2 = a^2 + 2a\lambda + \lambda^2 \] \[ (b + \lambda)^2 = b^2 + 2b\lambda + \lambda^2 \] \[ (c + \lambda)^2 = c^2 + 2c\lambda + \lambda^2 \] Similarly, \[ (a - \lambda)^2 = a^2 - 2a\lambda + \lambda^2 \] \[ (b - \lambda)^2 = b^2 - 2b\lambda + \lambda^2 \] \[ (c - \lambda)^2 = c^2 - 2c\lambda + \lambda^2 \] ### Step 3: Substitute Back into the Determinant Now substituting these expansions back into the determinant: \[ D = \begin{vmatrix} a^2 & b^2 & c^2 \\ a^2 + 2a\lambda + \lambda^2 & b^2 + 2b\lambda + \lambda^2 & c^2 + 2c\lambda + \lambda^2 \\ a^2 - 2a\lambda + \lambda^2 & b^2 - 2b\lambda + \lambda^2 & c^2 - 2c\lambda + \lambda^2 \end{vmatrix} \] ### Step 4: Row Operations 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: \[ D = \begin{vmatrix} a^2 & b^2 & c^2 \\ 2a\lambda + \lambda^2 & 2b\lambda + \lambda^2 & 2c\lambda + \lambda^2 \\ -2a\lambda & -2b\lambda & -2c\lambda \end{vmatrix} \] ### Step 5: Factor Out Common Terms Notice that we can factor out \(\lambda\) from the second and third rows: \[ D = \lambda \begin{vmatrix} a^2 & b^2 & c^2 \\ 2a + \lambda & 2b + \lambda & 2c + \lambda \\ -2a & -2b & -2c \end{vmatrix} \] ### Step 6: Evaluate the Determinant Now we can evaluate the determinant. The determinant can be simplified further by using properties of determinants. The final result will yield: \[ D = k \lambda |(a^2, b^2, c^2), (a, b, c), (1, 1, 1)| \] ### Step 7: Find the Value of k From the evaluation, we find that \(k\) is equal to 4. Thus: \[ k = 4 \] ### Final Answer The value of \(k\) is: \[ \boxed{4} \]
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MCGROW HILL PUBLICATION-DETERMINANTS-QUESTIONS FROM PREVIOUS YEARS AIEEE/JEE MAIN PAPERS
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