For questions like multiple-choice questions, it is advantageous to know the fastest way to solve them. . You set a coordinate axis

pay attention to

Calculate slowly.

In fact, it is a waste of time. Generally, space problems can be solved by vector method, but there are exceptions. This is the case with the college entrance examination in Guangdong in a certain year. Vector method can't do it at all, which killed most students. . .

Recommended unless it is obvious that it can be done by vector method (e.g.

Cubes, cuboids, etc. There are many right angles) you can consider using vector method. Vector method is not recommended for multiple-choice empty questions

waste time/waste of time

The idea of solving big problems: first, use geometric methods (generally use auxiliary lines) to observe whether it can be done. If you can't figure it out, then establish a rectangular coordinate system. If there are not many or no right angles, do it with a and b space vectors.

Another advantage of geometric method is thinking. Generally, a big question has many questions. Using geometric methods, you will find one link after another, and the latter question can use an answer in the process of the previous question, so that the speed of solving problems is much faster. . .

If you have any other questions, please call me! (*^__^*)

This is hard work. Give some points. . .