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If x+ (1)/(x) = sqrt3 find x^(17) + (...

If `x+ (1)/(x) = sqrt3` find
`x^(17) + (1)/(x^(17))`

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To solve the problem where \( x + \frac{1}{x} = \sqrt{3} \) and we need to find \( x^{17} + \frac{1}{x^{17}} \), we can follow these steps: ### Step 1: Find \( x^2 + \frac{1}{x^2} \) We start with the given equation: \[ x + \frac{1}{x} = \sqrt{3} \] We square both sides: \[ \left(x + \frac{1}{x}\right)^2 = (\sqrt{3})^2 \] This expands to: \[ x^2 + 2 + \frac{1}{x^2} = 3 \] Subtracting 2 from both sides gives: \[ x^2 + \frac{1}{x^2} = 1 \] ### Step 2: Find \( x^3 + \frac{1}{x^3} \) Using the identity: \[ x^3 + \frac{1}{x^3} = \left(x + \frac{1}{x}\right)\left(x^2 + \frac{1}{x^2}\right) - \left(x + \frac{1}{x}\right) \] Substituting the known values: \[ x^3 + \frac{1}{x^3} = \left(\sqrt{3}\right)(1) - \sqrt{3} = \sqrt{3} - \sqrt{3} = 0 \] ### Step 3: Find \( x^6 + \frac{1}{x^6} \) Using the identity: \[ x^6 + \frac{1}{x^6} = \left(x^3 + \frac{1}{x^3}\right)^2 - 2 \] Substituting the value we found: \[ x^6 + \frac{1}{x^6} = 0^2 - 2 = -2 \] ### Step 4: Find \( x^{12} + \frac{1}{x^{12}} \) Using the identity: \[ x^{12} + \frac{1}{x^{12}} = \left(x^6 + \frac{1}{x^6}\right)^2 - 2 \] Substituting the value we found: \[ x^{12} + \frac{1}{x^{12}} = (-2)^2 - 2 = 4 - 2 = 2 \] ### Step 5: Find \( x^{17} + \frac{1}{x^{17}} \) Using the identity: \[ x^{17} + \frac{1}{x^{17}} = \left(x^{12} + \frac{1}{x^{12}}\right)\left(x^5 + \frac{1}{x^5}\right) - \left(x^{7} + \frac{1}{x^{7}}\right) \] First, we need \( x^5 + \frac{1}{x^5} \) and \( x^7 + \frac{1}{x^7} \). ### Step 6: Find \( x^4 + \frac{1}{x^4} \) Using the identity: \[ x^4 + \frac{1}{x^4} = \left(x^2 + \frac{1}{x^2}\right)^2 - 2 \] Substituting the value we found: \[ x^4 + \frac{1}{x^4} = 1^2 - 2 = 1 - 2 = -1 \] ### Step 7: Find \( x^5 + \frac{1}{x^5} \) Using the identity: \[ x^5 + \frac{1}{x^5} = \left(x^4 + \frac{1}{x^4}\right)\left(x + \frac{1}{x}\right) - \left(x^3 + \frac{1}{x^3}\right) \] Substituting the values: \[ x^5 + \frac{1}{x^5} = (-1)(\sqrt{3}) - 0 = -\sqrt{3} \] ### Step 8: Find \( x^7 + \frac{1}{x^7} \) Using the identity: \[ x^7 + \frac{1}{x^7} = \left(x^6 + \frac{1}{x^6}\right)\left(x + \frac{1}{x}\right) - \left(x^5 + \frac{1}{x^5}\right) \] Substituting the values: \[ x^7 + \frac{1}{x^7} = (-2)(\sqrt{3}) - (-\sqrt{3}) = -2\sqrt{3} + \sqrt{3} = -\sqrt{3} \] ### Step 9: Calculate \( x^{17} + \frac{1}{x^{17}} \) Now we can substitute back into our equation: \[ x^{17} + \frac{1}{x^{17}} = \left(2\right)(-\sqrt{3}) - (-\sqrt{3}) = -2\sqrt{3} + \sqrt{3} = -\sqrt{3} \] Thus, the final answer is: \[ \boxed{-\sqrt{3}} \]
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