English: Plot of the Bessel functions of 2nd kind ${\displaystyle Y_{0}(x)}$ in red,

${\displaystyle Y_{1}(x)}$ in green and ${\displaystyle Y_{2}(x)}$ in blue. The file "besselY.dat" contains the values of the Bessel functions and can be produced with the following Octave commands:

t = 0:0.01:20;
Y = [ t; bessely(0,t); bessely(1,t); bessely(2,t) ];
Y = Y';
save -ascii "besselY.dat" Y;

It was then post-processed with Inkscape.