The choice of coordinate system, parametric equation and inequality is the choice of 22 questions and 23 questions in the national volume. In general, I will focus on coordinate system and parameter equation, and ask students to practice 23 questions properly, just in case.

Question 22 mainly tests four kinds of questions.

First, the common law, all the curve equations in the topic are transformed into rectangular coordinate system, and the problem is solved by using the content of analytic geometry, which belongs to simple analytic geometry problems.

Secondly, the parametric equations of circles and ellipses are transformed into the evaluation domain of trigonometric functions.

Thirdly, the parametric equation of a straight line and the geometric meaning of t mostly solve the problems related to the length of a line segment.

Fourthly, the geometric meaning of polar diameter and polar angle, all curves in the topic are converted into polar coordinate system for related calculation.

Over the years, most of the college entrance examination questions have been tested in the first, second and fourth categories, and the third category has been tested in the 20 18 national paper 2 and the national paper 3.

For the problems related to the length of line segment, sometimes the geometric meaning of T can be used, and sometimes the geometric meaning of polar diameter can also be used. The difference is that the trial scope of the latter is that the distance in the topic must be related to the distance between a point and a pole.