====== 2次関数 ======
[[https://itunes.apple.com/jp/app/gao-xiao-shu-xue-i-2ci-guan-shu/id583729993|{{:math:hmath:hmath_i:itunesartwork_2x_02.png?120|}}]]

  * [[math:hmath:hmath_i:hmath_i_01|]]
  * [[math:hmath:hmath_i:hmath_i_03|]]