Hi everyone,

I am trying to use the solve() function to compute the first zero crossing (root) of the BesselJ function. I am aware that BesselJZeros does work, but I am really trying to use solve. Currently if I use the following:

root1:=solve(BesselJ(0,x),x,allsolutions=true);

Now if i use:

evalf(map(allvalues,root1));

I obtain:

-2.30382558

If I try to use solve(BesselJ(0,x),x,allsolutions=true, useassumptions) assuming x>0;