2. General equation of circle x2+y2+Dx+Ey+F=0 Note: D2+E2-4f > 0。

3. Trigonometric function: the formula of the sum of two angles:

sin(A+B)= Sina cosb+cosa sinb sin(A-B)= Sina cosb-sinb cosa

cos(A+B)= cosa cosb-Sina sinb cos(A-B)= cosa cosb+Sina sinb

tan(A+B)=(tanA+tanB)/( 1-tanA tanB)tan(A-B)=(tanA-tanB)/( 1+tanA tanB)

cot(A+B)=(cotA cotB- 1)/(cot B+cotA)cot(A-B)=(cotA cotB+ 1)/(cot B-cotA)

Extended data:

Matters needing attention in senior high school mathematics:

First of all, it is very important to cultivate good listening habits in classroom teaching. Of course, listening is the main thing. Listening can help you concentrate. You should understand and listen to the key points of the teacher.

Pay attention to thinking and analyzing problems when listening, but only listening without remembering, or just remembering without listening, it is inevitable to pay attention to one thing and lose sight of another, and the classroom efficiency is low. Therefore, we should take notes appropriately and purposefully to understand the main spirit and intention of the teacher in class. Scientific notes can improve the efficiency of four 5-minute classes.

Secondly, to improve mathematics ability, of course, through the classroom, make full use of this position. The process of learning mathematics is alive, so is the object of teachers' teaching, which changes with the development of teaching process, especially when teachers pay attention to ability teaching, the teaching materials can not be reflected.