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If x = 2+ sqrt(3) the (x + (1)/(x)) equa...

If `x = 2+ sqrt(3)` the `(x + (1)/(x))` equals

A

`-2sqrt(3)`

B

2

C

4

D

`4-2sqrt(3)`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem where \( x = 2 + \sqrt{3} \) and we need to find \( x + \frac{1}{x} \), we can follow these steps: ### Step 1: Write down the expression We start with the expression we want to evaluate: \[ x + \frac{1}{x} \] ### Step 2: Substitute the value of \( x \) Substituting \( x = 2 + \sqrt{3} \) into the expression gives us: \[ (2 + \sqrt{3}) + \frac{1}{2 + \sqrt{3}} \] ### Step 3: Simplify \( \frac{1}{2 + \sqrt{3}} \) To simplify \( \frac{1}{2 + \sqrt{3}} \), we multiply the numerator and denominator by the conjugate of the denominator, which is \( 2 - \sqrt{3} \): \[ \frac{1}{2 + \sqrt{3}} \cdot \frac{2 - \sqrt{3}}{2 - \sqrt{3}} = \frac{2 - \sqrt{3}}{(2 + \sqrt{3})(2 - \sqrt{3})} \] ### Step 4: Calculate the denominator Now, we calculate the denominator: \[ (2 + \sqrt{3})(2 - \sqrt{3}) = 2^2 - (\sqrt{3})^2 = 4 - 3 = 1 \] Thus, we have: \[ \frac{1}{2 + \sqrt{3}} = 2 - \sqrt{3} \] ### Step 5: Substitute back into the expression Now we substitute back into our expression: \[ x + \frac{1}{x} = (2 + \sqrt{3}) + (2 - \sqrt{3}) \] ### Step 6: Combine like terms Combining the terms: \[ (2 + 2) + (\sqrt{3} - \sqrt{3}) = 4 + 0 = 4 \] ### Final Answer Thus, the value of \( x + \frac{1}{x} \) is: \[ \boxed{4} \]
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