Previously I posted a graph of some Bessel functions on the interval zero to twenty, or [0,20] . Here is the same code but on the symmetric counterpart of the the previous interval, [-20, 20]. This allows use to plainly see that even-numbered Bessel functions are even functions (satisfy f(-x)=f(x)) while odd-numbered Bessel functions are odd ( satisfy f(-x)=-f(x) ).

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