If $\sqrt{x} + \frac{1}{\sqrt{x}} = 3, x > 0$, then $x^2(x^2 - 47) = ?$
Answer & explanation
Correct answer: option 4
If $K+\frac{1}{K}=n$
then, $K^2+\frac{1}{K^2}$ = n2 – 2
If $\sqrt{x} + \frac{1}{\sqrt{x}} = 3, x > 0$
then $x^2(x^2 - 47) = ?$
If $\sqrt{x} + \frac{1}{\sqrt{x}} = 3, x > 0$
Then, x + \(\frac{1}{x}\) = 32 – 2 = 7
x2 + \(\frac{1}{x^2}\) = 72 – 2 = 47
Put the value of 47 in $x^2(x^2 - 47) $
= $x^2(x^2 - x^2 - \frac{1}{x^2}) $ = -1