[Maxima-bugs] Errors on computing high-degree Legendre polynomials

[Ednilton S. de O. <esd...@gm...>]

Dear All,

I tried to work with high-degree Legendre polynomials, but
I realized that Maxima returns wrong values for them.

For low-degree Legendre polynomials, I can obtain precise
results with 'expand'. For example, I use
"expand(legendre_p(10,x))"
instead of
"legendre_p(10,x)".
See: 
https://www.dropbox.com/s/f4wt7bruv6ropfp/maxima-legendre_problem-l30.png?dl=0

However, 'expand' does not work for very high degrees, for example, l = 45.
See : 
https://www.dropbox.com/s/b38p3fv6adejesg/maxima-legendre_problem-l45.png?dl=0

This problem occurs with both Maxima 5.32.1 using Lisp GNU Common Lisp 
installed via "APT" in Kubuntu
and Maxima 5.34.1 compiled using Lisp CLISP 2.49.

Any help is appreciated.

Best wishes,

Ednilton S. de Oliveira