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Suppose a,b,c, gt0 and |(a^(3)-1,a^(2)...

Suppose `a,b,c, gt0` and
`|(a^(3)-1,a^(2),a),(b^(3)-1,b^(2),b),(c^(3)-1,c^(2),c)|=0` then least possible value of `a+b+c` is ____________

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To solve the problem, we need to analyze the determinant given in the question: \[ \begin{vmatrix} a^3 - 1 & a^2 & a \\ b^3 - 1 & b^2 & b \\ c^3 - 1 & c^2 & c \end{vmatrix} = 0 \] ### Step 1: Rewrite the determinant We can rewrite the first column of the determinant as follows: \[ a^3 - 1 = (a - 1)(a^2 + a + 1) \] Thus, we can express the determinant as: \[ \begin{vmatrix} (a - 1)(a^2 + a + 1) & a^2 & a \\ (b - 1)(b^2 + b + 1) & b^2 & b \\ (c - 1)(c^2 + c + 1) & c^2 & c \end{vmatrix} \] ### Step 2: Factor out common terms Since we are interested in the determinant being zero, we can factor out \( (a - 1), (b - 1), (c - 1) \) from the first column: \[ (a - 1)(b - 1)(c - 1) \begin{vmatrix} a^2 + a + 1 & a^2 & a \\ b^2 + b + 1 & b^2 & b \\ c^2 + c + 1 & c^2 & c \end{vmatrix} = 0 \] ### Step 3: Analyze the determinant condition For the determinant to be zero, either \( a - 1 = 0 \), \( b - 1 = 0 \), or \( c - 1 = 0 \). This means at least one of \( a, b, c \) must be equal to 1. ### Step 4: Use AM-GM inequality Assuming \( a = 1 \) (without loss of generality), we want to minimize \( a + b + c \). By the AM-GM inequality: \[ \frac{a + b + c}{3} \geq \sqrt[3]{abc} \] Given that \( a = 1 \), we have: \[ \frac{1 + b + c}{3} \geq \sqrt[3]{1 \cdot b \cdot c} = \sqrt[3]{bc} \] ### Step 5: Set \( b \) and \( c \) to their minimum values To minimize \( 1 + b + c \), we can set \( b = 1 \) and \( c = 1 \): \[ 1 + 1 + 1 = 3 \] ### Conclusion Thus, the least possible value of \( a + b + c \) is: \[ \boxed{3} \]
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