If [tex]$x = \frac{\sqrt{5} + \sqrt{3}}{\sqrt{5} - \sqrt{3}}$[/tex], then the value of [tex]$x^2 + \frac{1}{x^2}$[/tex] is:

A) 54
B) 14
C) 62
D) 66



Answer :

Let's find the value of [tex]\( x^2 + \frac{1}{x^2} \)[/tex] given [tex]\( x = \frac{\sqrt{5} + \sqrt{3}}{\sqrt{5} - \sqrt{3}} \)[/tex].

1. First, define the expression for [tex]\( x \)[/tex]:
[tex]\[ x = \frac{\sqrt{5} + \sqrt{3}}{\sqrt{5} - \sqrt{3}} \][/tex]

2. Square the expression for [tex]\( x \)[/tex] to find [tex]\( x^2 \)[/tex]:
[tex]\[ x^2 = \left( \frac{\sqrt{5} + \sqrt{3}}{\sqrt{5} - \sqrt{3}} \right)^2 \][/tex]
Based on calculated results:
[tex]\[ x^2 \approx 61.98386676965928 \][/tex]

3. Calculate the reciprocal of [tex]\( x^2 \)[/tex], which is [tex]\( \frac{1}{x^2} \)[/tex]:
[tex]\[ \frac{1}{x^2} \approx 0.016133230340664932 \][/tex]

4. Add [tex]\( x^2 \)[/tex] and [tex]\( \frac{1}{x^2} \)[/tex]:
[tex]\[ x^2 + \frac{1}{x^2} \approx 61.98386676965928 + 0.016133230340664932 \][/tex]
[tex]\[ x^2 + \frac{1}{x^2} \approx 61.99999999999994 \][/tex]

5. Now, let's match this result to the given options:
[tex]\[ \text{A) 54} \][/tex]
[tex]\[ \text{B) 14} \][/tex]
[tex]\[ \text{C) 62} \][/tex]
[tex]\[ \text{D) 66} \][/tex]

Based on our calculated values, the closest and the most accurate answer is:
[tex]\[ \boxed{62} \][/tex]