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|(a,b,c),(c,a,b),(b,c,a)|=(a+b+c)(a+bome...

`|(a,b,c),(c,a,b),(b,c,a)|=(a+b+c)(a+bomega+comega^2)(a+bomega^2+comega)`True or False

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To determine if the equation \( |(a,b,c),(c,a,b),(b,c,a)| = (a+b+c)(a+b\omega+c\omega^2)(a+b\omega^2+c\omega) \) is true or false, we will evaluate both sides step by step. ### Step 1: Evaluate the Left-Hand Side (LHS) We have the determinant: \[ D = \begin{vmatrix} a & b & c \\ c & a & b \\ b & c & a \end{vmatrix} \] To compute this determinant, we can use the method of cofactor expansion along the first row. ### Step 2: Expand the Determinant Using cofactor expansion along the first row: \[ D = a \begin{vmatrix} a & b \\ c & a \end{vmatrix} - b \begin{vmatrix} c & b \\ b & a \end{vmatrix} + c \begin{vmatrix} c & a \\ b & c \end{vmatrix} \] Calculating each of the 2x2 determinants: 1. \( \begin{vmatrix} a & b \\ c & a \end{vmatrix} = a^2 - bc \) 2. \( \begin{vmatrix} c & b \\ b & a \end{vmatrix} = ca - b^2 \) 3. \( \begin{vmatrix} c & a \\ b & c \end{vmatrix} = c^2 - ab \) Substituting these back into the determinant: \[ D = a(a^2 - bc) - b(ca - b^2) + c(c^2 - ab) \] ### Step 3: Simplify the Expression Expanding this gives: \[ D = a^3 - abc - bca + b^3 + c^3 - abc \] Combining like terms: \[ D = a^3 + b^3 + c^3 - 3abc \] ### Step 4: Evaluate the Right-Hand Side (RHS) Now we evaluate the right-hand side: \[ RHS = (a+b+c)(a+b\omega+c\omega^2)(a+b\omega^2+c\omega) \] ### Step 5: Simplify the RHS Using the property of roots of unity, where \( \omega \) is a primitive cube root of unity (\( \omega^3 = 1 \) and \( 1 + \omega + \omega^2 = 0 \)), we can expand the product. The expression simplifies to: \[ RHS = (a+b+c) \cdot \left( (a+b+c)(a+b+c) - 3abc \right) \] This leads to: \[ RHS = (a+b+c)^3 - 3(a+b+c)abc \] ### Step 6: Compare LHS and RHS From our calculations: - LHS: \( a^3 + b^3 + c^3 - 3abc \) - RHS: \( (a+b+c)^3 - 3abc \) Using the identity \( a^3 + b^3 + c^3 - 3abc = (a+b+c)(a^2 + b^2 + c^2 - ab - ac - bc) \), we can see that both sides are equal when simplified. ### Conclusion Since both sides are equal, the statement is **True**.
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