"show $\displaystyle x_n = \frac{n+1}{9^n}$ satisfies $\displaystyle x_{n+1}\leq\frac{1}{2}x_n$ for all $\displaystyle n \geq 1$". i don't know how to show it. i can see that it is true but i can't see how to approach it. i have tried a few things like writing one expression in terms of the other etc. but it doesn't get me where i need to be. can someone give me a pointer please? thank you