1 with(DEtools); Parameter(M); de := diff(q(p), p)+(M^2*p^2-q(p)^2)/(2*p*q(p)) = 0; dsolve({de, q(px) = 0}, q(p)); DEplot(de, q(p), p = -10 .. 10, q = -10 .. 10, color = black, thickness = 2*`，arrows` and 2*`，arrows` = large)
原文：https://www.cnblogs.com/zhubinglong/p/9270424.html