If $ p - \frac{1}{p}= 6$, then what is the value of $p^4 +\frac{1}{p^4}$ ?
Answer & explanation
Correct answer: option 3
If x - \(\frac{1}{x}\) = n
Then, x + \(\frac{1}{x}\) = \(\sqrt {n^2 + 4}\)
If $ p - \frac{1}{p}= 6$
Then, p + \(\frac{1}{p}\) = \(\sqrt {6^2 + 4}\) = \(\sqrt {40}\)
If $K+\frac{1}{K}=n$
then, $K^2+\frac{1}{K^2}$ = n2 – 2
then, $p^2+\frac{1}{p^2}$ = (\(\sqrt {40}\))2 – 2 = 38
and , $p^4+\frac{1}{p^4}$ = (38)2 – 2 = 1444 - 2 = 1442