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Let f(x) = x^3 + ax^2 + bx + c and g(x) ...

Let `f(x) = x^3 + ax^2 + bx + c` and `g(x) = x^3 + bx^2 + cx + a`, where a, b, c are integers. Suppose that the following conditions hold-
(a) `f(1) = 0`,
(b) the roots of g(x) = 0 are the squares of the roots of f(x) = 0. Find the value of: `a^(2013) + b^(2013) + c^(2013)`

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The correct Answer is:
To solve the problem, we need to analyze the given functions and the conditions provided. ### Step 1: Analyze the function \( f(x) \) The function is given as: \[ f(x) = x^3 + ax^2 + bx + c \] We know that \( f(1) = 0 \). Therefore: \[ f(1) = 1^3 + a(1^2) + b(1) + c = 1 + a + b + c = 0 \] This gives us our first equation: \[ 1 + a + b + c = 0 \quad \text{(Equation 1)} \] ### Step 2: Analyze the function \( g(x) \) The function is given as: \[ g(x) = x^3 + bx^2 + cx + a \] The roots of \( g(x) = 0 \) are the squares of the roots of \( f(x) = 0 \). Let the roots of \( f(x) = 0 \) be \( r_1, r_2, r_3 \). Then the roots of \( g(x) = 0 \) are \( r_1^2, r_2^2, r_3^2 \). ### Step 3: Use Vieta's formulas for \( f(x) \) From Vieta's formulas, for the cubic polynomial \( f(x) \): - The sum of the roots \( r_1 + r_2 + r_3 = -a \) - The sum of the products of the roots taken two at a time \( r_1 r_2 + r_2 r_3 + r_3 r_1 = b \) - The product of the roots \( r_1 r_2 r_3 = -c \) ### Step 4: Use Vieta's formulas for \( g(x) \) For the polynomial \( g(x) \): - The sum of the roots \( r_1^2 + r_2^2 + r_3^2 = -b \) - The sum of the products of the roots taken two at a time \( r_1^2 r_2^2 + r_2^2 r_3^2 + r_3^2 r_1^2 = c \) - The product of the roots \( r_1^2 r_2^2 r_3^2 = -a \) ### Step 5: Relate the roots of \( f(x) \) and \( g(x) \) Using the identity for the sum of squares: \[ r_1^2 + r_2^2 + r_3^2 = (r_1 + r_2 + r_3)^2 - 2(r_1 r_2 + r_2 r_3 + r_3 r_1) \] Substituting the values from Vieta's: \[ r_1^2 + r_2^2 + r_3^2 = (-a)^2 - 2b = a^2 - 2b \] Setting this equal to the sum of the roots of \( g(x) \): \[ a^2 - 2b = -b \quad \Rightarrow \quad a^2 - b = 0 \quad \Rightarrow \quad b = a^2 \quad \text{(Equation 2)} \] ### Step 6: Relate the product of the roots The product of the roots gives: \[ r_1^2 r_2^2 r_3^2 = (r_1 r_2 r_3)^2 = (-c)^2 = c^2 \] Setting this equal to the product of the roots of \( g(x) \): \[ c^2 = -a \quad \text{(Equation 3)} \] ### Step 7: Substitute Equations 2 and 3 into Equation 1 Substituting \( b = a^2 \) into Equation 1: \[ 1 + a + a^2 + c = 0 \] Now substituting \( c = -\sqrt{-a} \) (from Equation 3): \[ 1 + a + a^2 - \sqrt{-a} = 0 \] ### Step 8: Solve for \( a, b, c \) From Equation 3, we know \( c = -a^2 \). Thus: \[ 1 + a + a^2 - (-a) = 0 \quad \Rightarrow \quad 1 + 2a + a^2 = 0 \] This is a quadratic equation: \[ a^2 + 2a + 1 = 0 \quad \Rightarrow \quad (a + 1)^2 = 0 \quad \Rightarrow \quad a = -1 \] Substituting \( a = -1 \) back into Equations 2 and 3: \[ b = (-1)^2 = 1, \quad c = -(-1)^2 = -1 \] ### Step 9: Calculate \( a^{2013} + b^{2013} + c^{2013} \) Now we have: \[ a = -1, \quad b = 1, \quad c = -1 \] Calculating: \[ a^{2013} + b^{2013} + c^{2013} = (-1)^{2013} + 1^{2013} + (-1)^{2013} = -1 + 1 - 1 = -1 \] ### Final Answer Thus, the value of \( a^{2013} + b^{2013} + c^{2013} \) is: \[ \boxed{-1} \]
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