 Logistic inverse branches contract in an angular coordinate

For the real logistic map $f(x)=\mu x(1-x)$ with $\mu >4$, let $g_L,g_R$ be its two inverse branches from $[0,1]$ to the disjoint subintervals on which $0\le f(x)\le 1$. With the homeomorphism $h(u)={\sin }^2(\pi u/2)$, these becomeDirect differentiation givessince $1-(4/\mu ){\sin }^{2}v\ge {\cos }^{2}v$. Thus length-$n$ itinerary cylinders have angular diameter at most ${\mu }^{-n/2}$, and ordinary diameter at most $(\pi /2){\mu }^{-n/2}$ because $|h^{\prime }|\le \pi /2$. The nested interval theorem then gives exactly one point for each infinite itinerary. This proves the coding by the one-sided full shift even when the ordinary-coordinate inverse branches are not contractions.