My DM42 as well as Free42 encounters difficulties with a SOLVE problem (finding roots of a Bessel function).

This Solve is calling a LBL which integrates a function (for Bessel Jn(x)).

On screen I see the process running... one of the boundary reaching the solution, but for the case I'm interested in, it "never" stops,

for a long time (I couldn't wait to the end, too many minutes). The second boundary doesn't converge very well to the root, why ?

The 2 initial guess values are well around the true root, one giving f(x) positive and one giving f(x) negative, so a run without hurdles...

A bit frustrated, and knowing SOLVE is very fast otherwise, I tried to solve myself with a Regula Falsi method, it converges very fast and reaches the zero after 4 iterations.

https://en.wikipedia.org/wiki/Regula_fa ... on)_method

Before giving some pieces of code, I'd like to know

**how**DM42 is searching and also

**when**does it decide to stop.

A buddy tried my code on his HP-42 and could reach a solution without issues...in less than a minute.

thank you !