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If W is an Imaginary Cube Root of Unity, Find the Value of ∣ ∣ ∣ ∣ ∣ 1 W W 2 W W 2 1 W 2 1 W ∣ ∣ ∣ ∣ ∣ - Mathematics

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प्रश्न

If w is an imaginary cube root of unity, find the value of \[\begin{vmatrix}1 & w & w^2 \\ w & w^2 & 1 \\ w^2 & 1 & w\end{vmatrix}\]

उत्तर

\[\begin{vmatrix}1 & w & w^2 \\ w & w^2 & 1 \\ w^2 & 1 & w\end{vmatrix}\] 
\[ = \begin{vmatrix} 1 + w + w^2 & w & w^2 \\ w + w^2 + 1 & w^2 & 1\\ w^2 + 1 + w & 1 & w \end{vmatrix} \left[\text{ Applying }C_1 \to C_1 + C_2 + C_3 \right]\] 
\[ = \begin{vmatrix} 0 & w 7 w^2 \\ 0 & w^2 & 1\\ 0 & 1 7 w \end{vmatrix} \left[ \because 1 + w + w^2 = 0,\text{ w is the imaginary cube root of unity }\right] \] 
\[ = 0\] 

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पाठ 6: Determinants - Exercise 6.6 [पृष्ठ ९०]

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आरडी शर्मा Mathematics [English] Class 12
पाठ 6 Determinants
Exercise 6.6 | Q 11 | पृष्ठ ९०

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