Talk:Euler–Tricomi equation

I don't think the Euler-Tricomi equation can be considered parabolic at x=0 as stated in the article. If x=0, the equation degenerates to a 2nd order ODE, so PDE type classification doesn't really make sense. See for example http://people.maths.ox.ac.uk/chengq/outreach/The%20Tricomi%20Equation.pdf — Preceding unsigned comment added by Tlkdrt (talk • contribs) 11:28, 20 November 2021 (UTC)