The fixed point problem is actually related to the solution equations of geometry and algebra.

1 first of all, we should understand the meaning of the topic, draw a picture and find the characteristics of the graph required by the topic, such as the four corners of a rectangle are right angles, the sum of the inner angles of a triangle is 180, and so on.

Then list the equations according to the requirements of the topic. The most important thing of the equation is to find the invariants, and the things on the left of the equation are equal to those on the right. The first step is to easily determine some invariants through geometric features.

Finally, solve the equation!

You can look at the following example.