For each integer $n\geq 1$ and $x\in [0,1]$, define $f\_n(x)=x\_n$ where $x\_n$ is the $n$th binary digit of x. If x is a number with two binary expansions, use the expansion that ends with infinitely many zeroes. Draw the graphs of the first three members of the sequence $\{f\_n-1/2\}$.

In fact I don't know how to represent the binary expansion of any number in the unit interval [0,1]. Thanks!