https://math.stackexchange.com/questions/3436714/algorithm-to-find-common-tangent-to-any-two-conics を 味読 し https://www.yu-hanami.com/entry/2019/05/22/170200 倣い； -4 x^3+x^2 y^2+24 x^2-10 x y^2+y^4=0が 可約曲線 reducible curve c1=0,c2…