Determine the inverse z-transform of
$$
F(z)=\frac{2 z}{2 z+1}
$$
$$
\frac{2 z}{2 z+1}=\frac{2 z}{2\left(z+\frac{1}{2}\right)}=\frac{z}{z+\frac{1}{2}}
$$
From 6 in Table 79.1, $Z\left\{a^{k}\right\}=\frac{z}{z-a}$ hence $\quad Z^{-1}\left\{\frac{z}{z-a}\right\}=a^{k}$
Comparing $\frac{z}{z+\frac{1}{2}}$ with $\frac{z}{z-a}$ shows that $\mathrm{a}=-\frac{1}{2}$ Thus, $Z^{-1}\left\{\frac{2 z}{2 z+1}\right\}=Z^{-1}\left\{\frac{z}{z+\frac{1}{2}}\right\}=\left(-\frac{1}{2}\right)^{k}$