1, Winter Olympics city and temperature: positive and negative. This Winter Olympics is hosted by Beijing and hosted by Zhangjiakou. Why choose Zhangjiakou instead of the northeast where the temperature is lower? In addition to distance, it also has a lot to do with temperature. Previous Winter Olympics are usually held in February, and the temperature-17℃~ 10℃ is the most ideal temperature.

2. Graphics in the Winter Olympics: axial symmetry and central symmetry. The medals of the Winter Olympics are round, the five rings of the Winter Olympics are axisymmetric figures composed of five circles, and the snowflake guide card is central symmetry.

3. Skiing track of platform: parabola. Take the third jump of the frog princess Gu Ailing as an example, the auxiliary speed of the skater can reach 24 meters per second. When the skater slides, we will see a beautiful parabola whose trajectory can be abstracted as a quadratic function image.

4. National flag: proportion. The national flags of the Winter Olympics are basically rectangular and look similar, but in fact the ratio of length to width is not exactly the same. For example, the ratio of the national flag of China is 2:3, that of the American flag is 10: 19, and that of Sweden is 5:8.

Indonesia, Monaco and Poland are all red and white striped flags, but the aspect ratio is different. Indonesia is 3:2, Monaco is 5:4 and Poland is 8:5.