Generally speaking, it will involve the transformation of classification ideas, overall thinking, modeling thinking and the combination of numbers and shapes.

Specific knowledge? Depends on the topic.

Recently, I like to use similarity and acute angle function in the dynamic questions of exams.

The difficulty is to prove similarity or find the coordinates of points with quadratic function in rectangular coordinate system.

Trigonometric function generally does not appear in this kind of topic, because it is too simple.

Why not focus on the idea of classification? That's the point.