Hua, a famous mathematician in China, once said: "The universe is big, the particles are tiny, the speed of rockets, the cleverness of chemical industry, the change of the earth, the mystery of biology, and the complexity of the sun and the moon are everywhere." Yes, especially in the 2 1 century, the application of mathematics is everywhere. For example, how magnificent the Expo venues are, and talented architects need to accurately calculate the height, width, length and angle of the building, all of which need to be applied to geometry and so on. Can this be made without mathematics? Mathematics is magical, mathematical knowledge is infinite, mathematical formulas are very wonderful, and mathematical thinking questions can dig out our wisdom. "Mathematics is the queen of science", and her beauty and mystery have attracted many people to explore the mystery of mathematics.