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If |{:(1,x,x^(2)),(x,x^(2),1),(x^(2),1,x...

If `|{:(1,x,x^(2)),(x,x^(2),1),(x^(2),1,x):}|` =3 then the value of `|{:(x^(3)-1,0,x-x^(4)),(0,x-x^(4),x^(3)-1),(x-x^(4),x^(3)-1,0):}|` is

A

6

B

9

C

18

D

27

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem step by step, we will first analyze the determinants provided and then find the required value. ### Step 1: Analyze the first determinant Given: \[ D_1 = \begin{vmatrix} 1 & x & x^2 \\ x & x^2 & 1 \\ x^2 & 1 & x \end{vmatrix} = 3 \] We need to compute this determinant. ### Step 2: Compute the first determinant Using the determinant formula for a 3x3 matrix: \[ D = a(ei - fh) - b(di - fg) + c(dh - eg) \] For our matrix: - \( a = 1, b = x, c = x^2 \) - \( d = x, e = x^2, f = 1 \) - \( g = x^2, h = 1, i = x \) Calculating: \[ D_1 = 1 \cdot (x^2 \cdot x - 1 \cdot 1) - x \cdot (x \cdot x - 1 \cdot x^2) + x^2 \cdot (x \cdot 1 - x^2 \cdot x) \] \[ = 1 \cdot (x^3 - 1) - x \cdot (x^2 - x^2) + x^2 \cdot (x - x^3) \] \[ = x^3 - 1 + x^2 \cdot (x - x^3) \] \[ = x^3 - 1 + x^3 - x^5 \] \[ = 2x^3 - x^5 - 1 \] Setting this equal to 3: \[ 2x^3 - x^5 - 1 = 3 \] \[ -x^5 + 2x^3 - 4 = 0 \] ### Step 3: Analyze the second determinant Now we need to compute: \[ D_2 = \begin{vmatrix} x^3 - 1 & 0 & x - x^4 \\ 0 & x - x^4 & x^3 - 1 \\ x - x^4 & x^3 - 1 & 0 \end{vmatrix} \] ### Step 4: Compute the second determinant Notice that we can factor out common terms. We can see that \(x - x^4 = x(1 - x^3)\). Thus, we can factor out \(x(1 - x^3)\) from the first and third rows: \[ D_2 = x(1 - x^3) \cdot \begin{vmatrix} x^3 - 1 & 0 & 1 \\ 0 & 1 & x^3 - 1 \\ 1 & x^3 - 1 & 0 \end{vmatrix} \] ### Step 5: Compute the new determinant Now we compute the determinant: \[ D = \begin{vmatrix} x^3 - 1 & 0 & 1 \\ 0 & 1 & x^3 - 1 \\ 1 & x^3 - 1 & 0 \end{vmatrix} \] Using the determinant formula: \[ D = (x^3 - 1) \begin{vmatrix} 1 & x^3 - 1 \\ x^3 - 1 & 0 \end{vmatrix} \] Calculating the 2x2 determinant: \[ = (x^3 - 1) \cdot (0 - (x^3 - 1)(1)) = (x^3 - 1)(-(x^3 - 1)) = -(x^3 - 1)^2 \] ### Step 6: Combine results Thus: \[ D_2 = x(1 - x^3)(-(x^3 - 1)^2) \] \[ = -x(1 - x^3)(x^3 - 1)^2 \] ### Step 7: Substitute \(x^3 - 1\) From our earlier result, we know that \(x^3 - 1 = \sqrt{3}\) (since \(D_1 = 3\)). Therefore: \[ D_2 = -x(1 - x^3)(\sqrt{3})^2 \] \[ = -x(1 - x^3) \cdot 3 \] ### Final Step: Evaluate Since \(x^3 - 1 = 3\), we have \(x^3 = 4\), thus \(1 - x^3 = -3\): \[ D_2 = -x(-3)(3) = 9x \] ### Conclusion The value of the second determinant is: \[ D_2 = 9 \]
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