The graph of artanh(x).

Generated using en:gnuplot with the script below, slightly modified by hand for xmlns and font size issues in the XML.

set terminal svg size 1600 1200 fname "Times New Roman" fsize 36
set output "area tangent.svg"

set zero 0
unset key
set samples 100000

set xtics axis ("" -1, "-0.75" -0.75, "-0.5" -0.5, "-0.25" -0.25, "0.25" 0.25, "0.5" 0.5, "0.75" 0.75, "" 1)
set ytics axis ("" -4, "-3" -3, "-2" -2, "-1" -1, "1" 1, "2" 2, "3" 3, "" 4)
set grid

set xzeroaxis lt -1 lw 4
set yzeroaxis lt -1 lw 4

set xrange [-1:1]
set yrange [-4:4]

plot log(x+sqrt(1+(x**2))) lt 3 lw 4