If $r + \frac{64}{r}= 16$, then the value of $r^4 +\frac{1}{r^3}$ is __________.
Answer & explanation
Correct answer: option 1
If $r + \frac{64}{r}= 16$,
then the value of $r^4 +\frac{1}{r^3}$ = ?
If $r + \frac{64}{r}= 16$,
Put the value of r = 8 ( This value will satisfy the given equation)
$8^4 +\frac{1}{8^3}$ = $4096 +\frac{1}{512}$ = $4096\frac{1}{512}$