12345 model spike method is a commonly used mathematical method, which is explained as follows:

This 12345 model is actually a simple application of the double-angle formula in the trigonometric function of senior high school, but due to the limitation of knowledge level, there is no way to tell it directly, so a model is summarized.

But in any case, this model is really useful in solving problems.

Related precautions

When analyzing the purpose of the topic, don't be too utilitarian, but try to explore the conclusion, thoroughly understand each topic and prevent routine thinking.

This may seem inefficient, but in the long run, you can quickly find relevant conclusions without looking at a topic condition. This method is actually the idea behind the geometric model, but it may not be as systematic as the geometric model.