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If x + (1)/(x)=1, find x^(82) + x^(68...

If `x + (1)/(x)=1`, find
`x^(82) + x^(68) + x^(55) + x^(35) +x^(30) + x^(27) + x^(21) + x^(3) + 2`=?

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To solve the equation \( x + \frac{1}{x} = 1 \) and find the value of \( x^{82} + x^{68} + x^{55} + x^{35} + x^{30} + x^{27} + x^{21} + x^{3} + 2 \), we can follow these steps: ### Step 1: Solve for \( x \) Starting with the equation: \[ x + \frac{1}{x} = 1 \] Multiply both sides by \( x \) (assuming \( x \neq 0 \)): \[ x^2 + 1 = x \] Rearranging gives: \[ x^2 - x + 1 = 0 \] Now, we can use the quadratic formula \( x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \) where \( a = 1, b = -1, c = 1 \): \[ x = \frac{1 \pm \sqrt{(-1)^2 - 4 \cdot 1 \cdot 1}}{2 \cdot 1} = \frac{1 \pm \sqrt{1 - 4}}{2} = \frac{1 \pm \sqrt{-3}}{2} \] Thus, we have: \[ x = \frac{1 \pm i\sqrt{3}}{2} \] ### Step 2: Find \( x^3 \) Next, we need to find \( x^3 \) using the identity: \[ x^3 + \frac{1}{x^3} = (x + \frac{1}{x})^3 - 3(x + \frac{1}{x}) \] Substituting \( x + \frac{1}{x} = 1 \): \[ x^3 + \frac{1}{x^3} = 1^3 - 3 \cdot 1 = 1 - 3 = -2 \] This means: \[ x^3 + \frac{1}{x^3} = -2 \] ### Step 3: Express higher powers of \( x \) Using the relation \( x^3 + \frac{1}{x^3} = -2 \), we can express higher powers of \( x \) in terms of \( x^3 \): - \( x^6 = (x^3)^2 \) - \( x^9 = x^3 \cdot x^6 \) - \( x^{12} = (x^3)^4 \) - Continuing this, we can express \( x^{n} \) for \( n = 82, 68, 55, 35, 30, 27, 21, 3 \) in terms of \( x^3 \). ### Step 4: Calculate each term We can express each exponent as multiples of 3: - \( x^{82} = (x^3)^{27} \cdot x \) - \( x^{68} = (x^3)^{22} \cdot x^2 \) - \( x^{55} = (x^3)^{18} \cdot x \) - \( x^{35} = (x^3)^{11} \cdot x^2 \) - \( x^{30} = (x^3)^{10} \) - \( x^{27} = (x^3)^9 \) - \( x^{21} = (x^3)^7 \) - \( x^{3} = (x^3)^1 \) ### Step 5: Substitute and simplify Using the fact that \( x^3 + \frac{1}{x^3} = -2 \), we can substitute: - \( x^{3k} = -1 \) for odd \( k \) - \( x^{3k} = 1 \) for even \( k \) Calculating: - \( x^{82} + x^{68} + x^{55} + x^{35} + x^{30} + x^{27} + x^{21} + x^{3} + 2 \) - Substitute \( x^{3k} \): \[ (-1) + 1 + (-1) + 1 + 1 + (-1) + (-1) + (-1) + 2 \] This simplifies to: \[ -1 + 2 = 1 \] ### Final Answer Thus, the value of \( x^{82} + x^{68} + x^{55} + x^{35} + x^{30} + x^{27} + x^{21} + x^{3} + 2 \) is: \[ \boxed{0} \]
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