Question

10х2(в степени n)/2^(n+1)+2^(n-1)

Answer 1

$\displaystyle \tt \frac{10\cdot2^{n}}{2^{n+1}+2^{n-1}}=\frac{20\cdot2^{n-1}}{2^{n-1}\cdot(2^{2}+1)}=\frac{20}{5}=4;$