Whether mathematics is useful or not is actually very useful, but many advanced mathematics can't appear in the interactive interface with the boss's surname like walking and breathing in daily life. You can only hide your achievements and fame behind you, and some of them can't be said casually. Take the most commonly used in our daily life as an example:

1, password design and decoding. In the communication industry, every time you send a text message or video, it is actually encrypted by signaling. The encryption means is in the background, using the knowledge of mapping in mathematics, transformation matrix of linear algebra and so on. There are even more advanced ones in it. After receiving your message, the other party will decrypt it through the key, which is the reverse operation of the above process. It's just that these actions are not displayed in the interactive interface with users, and the process is very fast, so I can't understand them.

2. Image compression or processing, face recognition. Principal component analysis is the most important technical means of the above application, which involves the calculation of eigenvalues in matrix algebra. It is also processed in the background. We just use PS and Meitu Xiu Xiu to operate in the foreground, and we can't feel the mathematical operation in the background.

3. In life and engineering applications, there are actually many algorithmic calculations, and these local engineering calculations are all realized by mathematics. For example, Fourier transform (image encryption), Euclidean distance (clustering analysis for marketing, neural network in big data), archimedean spiral (air duct design for range hoods), and so on.

4. For example, for the scheduling of production and processing, we need to use the planning solution in operational research, such as Lagrange multiplier method.

5. Kirchhoff's law or similar algorithm should be used in the design of power lines and the planning of road traffic. But these algorithms have the same tool, which is linear algebra.

6. There are more military-related things that most people may not understand. I want to know everything, but I can't, hehe.