Bessel function roots

Roofit and RooStats
1

Hi,
This may be a silly question, but here it is: I would like to
extract the roots of the TMath::BesselJ0(x) method. As of
now I can get the value of BesselJ0 for any x - what I really
want is the value of x at the zero-crossings (the roots). Am
I missing something obvious?
Thanks,
Penny

2

TF1 *bessel = new TF1("bessel","TMath::BesselJ0(x)",0,10); bessel->Draw(); printf("minX = %g\n",bessel->GetMinimumX(0,10));
Rene

3

Thank you! Your code answers several other questions for me
as well. I just made one small change by adding TMath::Abs,
as in TMath::Abs(TMath::BesselJ0(x)) . That gives me the zero
crossings as opposed to the minima.
Thanks again,
Penny