Posted by haifeng on 2018-03-11 16:57:15 last update 2018-03-23 14:24:24 | Answers (1) | 收藏
证明图中两块阴影部分的面积相等, 即 $A=B$.
翼とレンズ 翻译: 飞翼与透镜 wings and lens
翼(つばさ)
The picture is provided by Lei LIU.