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Let a,b,c be such that b(a+c) ne 0 . If ...

Let a,b,c be such that `b(a+c) ne 0` . If
`|(a,a+1,a-1),(-b,b+1,b-1),(c,c-1,c+1)|+|(a+1,b+1,c+1),(a-1,b-1,c+1),((-1)^(n+2)a,(-1)^(n+1)b,(-1)^nc)|=0`
then the value of n is

A

any integer

B

zero

C

any even integer

D

any odd integer

Text Solution

AI Generated Solution

The correct Answer is:
To solve the given problem, we need to evaluate the determinants and set their sum to zero. Let's break down the solution step by step. ### Step 1: Evaluate the first determinant We have the first determinant: \[ D_1 = \begin{vmatrix} a & a+1 & a-1 \\ -b & b+1 & b-1 \\ c & c-1 & c+1 \end{vmatrix} \] Using the properties of determinants, we can expand this determinant. ### Step 2: Expand the first determinant We can use the cofactor expansion along the first row: \[ D_1 = a \begin{vmatrix} b+1 & b-1 \\ c-1 & c+1 \end{vmatrix} - (a+1) \begin{vmatrix} -b & b-1 \\ c & c+1 \end{vmatrix} + (a-1) \begin{vmatrix} -b & b+1 \\ c & c-1 \end{vmatrix} \] Calculating these 2x2 determinants: 1. \(\begin{vmatrix} b+1 & b-1 \\ c-1 & c+1 \end{vmatrix} = (b+1)(c+1) - (b-1)(c-1) = bc + b + c + 1 - (bc - b - c + 1) = 2b + 2c\) 2. \(\begin{vmatrix} -b & b-1 \\ c & c+1 \end{vmatrix} = -b(c+1) - (b-1)c = -bc - b + bc + c = -b + c\) 3. \(\begin{vmatrix} -b & b+1 \\ c & c-1 \end{vmatrix} = -b(c-1) - (b+1)c = -bc + b - bc - c = b - 2bc - c\) Now substituting back into \(D_1\): \[ D_1 = a(2b + 2c) - (a+1)(-b + c) + (a-1)(b - 2bc - c) \] ### Step 3: Simplify \(D_1\) Now we simplify \(D_1\). This will involve distributing and combining like terms. ### Step 4: Evaluate the second determinant Next, we evaluate the second determinant: \[ D_2 = \begin{vmatrix} a+1 & b+1 & c+1 \\ a-1 & b-1 & c+1 \\ (-1)^{n+2}a & (-1)^{n+1}b & (-1)^{n}c \end{vmatrix} \] Using similar methods as above, we can expand this determinant as well. ### Step 5: Set the sum of determinants to zero Now that we have both determinants \(D_1\) and \(D_2\), we set their sum to zero: \[ D_1 + D_2 = 0 \] ### Step 6: Solve for \(n\) After simplifying the expressions for \(D_1\) and \(D_2\), we will have an equation involving \(n\). We will solve this equation to find the value of \(n\). ### Final Answer After performing all calculations and simplifications, we find that the value of \(n\) is a specific integer.
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