**Computer project** … has fixed points where

Computer project $F(x)=x-\tan x$ has fixed points where $\tan x^{\ast }=0$. So $x^{\ast }$ is any multiple of $\pi$. From $x_0=2.0$ and $1.8$ and $1.9$, which multiple do you reach? Test points in $1.7<x_0<1.9$ to find basins of attraction to $\pi ,2\pi ,3\pi ,4\pi$.
Between any two basins there are basins for every multiple of $\pi$. And more basins between these (a fractal). Mark them on the line from 0 to $\pi$. Magnify the picture around $x_0=1.9$ (in color?).

Its source prints no answer for this problem, so there's nothing to check against.

Gilbert Strang, Calculus, 3rd edition (Wellesley-Cambridge Press; MIT OpenCourseWare RES.18-001) · §3.6 Iterations x, #41