Proportional function is a special linear function [the general form of linear function is y=kx+b(b is not 0, k is constant)].

Image exercise: 1. List (coefficient to be determined) 2. Plot point 3. Connecting wire

The image of the proportional function is a straight line, which must pass through the coordinate origin.

When k>0, the image passes through one or three quadrants, and y increases with the increase of x.

When k < 0, the image passes through two or four quadrants, and y decreases with the increase of x.

(2) y = k/x (k is a constant, k≠0), we say that y is an inverse proportional function of x.

(The range of independent variable X is all real numbers not equal to 0)

The image of inverse proportional function is a hyperbola. It can approach the coordinate axis infinitely, but it will never intersect.

When k>0, the image is in one or three quadrants, and in each quadrant, y decreases with the increase of x.

When k < 0, the image is in two or four quadrants, and in each quadrant, y increases with the increase of x.