Tapering step: give some data, ask to write an equation, and then find something else according to the equation. Generally speaking, given the midpoint coordinates, the relationship between the midpoint coordinates and the slope of a straight line can be obtained by using the point difference method. Given the straight line passing through the focus, we can find the fixed point by setting the straight line equation and bringing it into the quadratic equation of one variable. The relationship between root and coefficient can be found by using Vieta theorem, which is a method of setting without finding. In order to avoid discussing the existence and non-existence of slope, the linear equation is set to the form of x = my-. The fixed-point problem within the scope of high school can be determined boldly on the coordinate axis, and it can't be wrong. There are several other situations that must be remembered: 1 and a three-point * * * circle, that is, the line segment connecting two points is the diameter, and the other point is on the circle. 2. The slopes of two straight lines are complementary, that is, two straight lines and the coordinate axis form an isosceles triangle. 3. There is a four-point * * * circle, that is, one line segment is the diameter and the other two points are on the circle. Too much. It takes three days and three nights. Let's talk about these first, some skills. Chatting online.