2021-10-20 c;1728 x^6-6912 x^4 y^2-10368 x^4 y+2752 x^3 y^3+5184 x^3 y^2+3888 x^3 y-864 x^3+6912 x^2 y^4+20736 x^2 y^3+13248 x^2 y^2-5504 x y^5-19648 x y^4-23328 x y^3-13392 x y^2-2592 x y+944 y^6+4128 y^5+6984 y^4+6520 y^3+3483 y^2+972 y+108=0 の 双対曲線の二重接線を多様な発想で是非