How difficult are these questions about trigonometric functions in fourth grade mathematics?
It's not very difficult. The senior high school entrance examination can only be placed at the intermediate level. Judging from the types of questions, they are all about the comprehensive application of basic knowledge. As long as the basic knowledge is well mastered, these are all a piece of cake. Of course, the calculation ability and carefulness should be sufficient. Feeling 124 is all about Pythagorean theorem. 4 is the union of Pythagorean theorem and quadratic equation. There seems to be something wrong with your plastic. Is that 1: 3? 22.5 and 67.5 are not easy to solve, and trigonometric functions and sine theorems are needed.