My classmate should be a sophomore. I wonder how you found me and asked me for help.

You are the first classmate to ask me for help, and I must answer carefully.

Ellipse is a key content of high school mathematics. The specific conclusions you need to know are as follows.

First, the first definition and second definition of ellipse

This is often used in solving problems, especially when numbers and shapes are combined, and the efficiency of solving problems will be greatly improved after use.

Second, the relationship between the parameters of the ellipse (A, B, C) is used in almost every question and needs to be remembered.

3. The line segment length of an ellipse cut by a straight line is usually a simultaneous equation of a circle and a straight line. Then get a quadratic equation about x or y. Then the equation l = sqrt (1+k2) | x1-x2 | or L = sqrt (1+( 1/)).

Fourth, the tangent equation of the ellipse passing through (m, n) is MX/A+NY/B 2 = 1, which is very practical and must be remembered!

5. There are many other conclusions in the ellipse, which can be obtained by borrowing or looking up courseware. However, if it is only for the college entrance examination, as long as we can flexibly substitute the relationship between the parameters such as focus, directrix, A, B and C, and use the combination of numbers and shapes and the thought of function, we should be able to solve the general college entrance examination questions.

6. Others: If you want to find network resources, you can try to search for "elliptic conclusion filetype:ppt".

I hope my answer can help you, and I wish you a smooth study!