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If $x = 4 + \sqrt{15}$, what is the value of $(x^2 +\frac{1}{x^2})$ ? |
48 54 72 62 |
62 |
If $x = 4 + \sqrt{15}$ then, x2 = 42 + 15 + 2 × 4 × $\sqrt{15}$ x2 = 31 + 8$\sqrt{15}$ \(\frac{1}{x^2}\) = 31 - 8$\sqrt{15}$ $(x^2 +\frac{1}{x^2})$ = 31 + 8$\sqrt{15}$ + 31 - 8$\sqrt{15}$ = 62 |
