Practicing Success
If $\sqrt{x} −\frac{1}{\sqrt{x}} = \sqrt{5}$, x ≠ 0, then what is the value of $\frac{(x^4+\frac{1}{x^2})}{(x^2+1)}$? |
42 44 48 46 |
46 |
If $\sqrt{x} −\frac{1}{\sqrt{x}} = \sqrt{5}$ Then, $\sqrt{x} + \frac{1}{\sqrt{x}} = \sqrt{5^2 + 4}$ = 3 x + \(\frac{1}{x}\) = 32 - 2 = 7 If x + \(\frac{1}{x}\) = n then, $x^3 +\frac{1}{x^3}$ = n3 - 3 × n $x^3 +\frac{1}{x^3}$ = 73 - 3 × 7 = 322 Now according to the question we have to find = $\frac{(x^4+\frac{1}{x^2})}{(x^2+1)}$ Take x common from numerator and denominator then we left with = $\frac{(x^3+\frac{1}{x^3})}{(x+\frac{1}{x})}$ = \(\frac{322}{7}\) = 46 |