There are three representations of subfunctions, as follows: analytical method: the method of expressing functions with formulas containing independent variables x is called analytical method; List method: the method of tabulating a series of function values y corresponding to x values to express the function relationship is called list method; Image method: the method of expressing functional relations with images is called image method.
Key points of knowledge: understand the meaning of function; Understand the function image with practice; It changes with the change of image understanding number.
Misunderstanding reminder: the misunderstanding of the concept of linear function omits the restriction that the coefficient of linear term is not 0; There is misunderstanding about the image and essence of linear function; Ignore the value range of function independent variables; (Sometimes xEZ, whose image is a collection of discontinuous points) 4. For linear functions, the independent variable cannot be equal to zero.
And the similarities and differences of equations:
1, linear function and linear equation have similar expressions; A linear function represents the relationship between a pair of (x, y), and it has countless pairs of solutions. The unary linear equation represents the unknown value of x, with a maximum of 1 value;
2. The abscissa of the intersection of the linear function and the X axis is the root of the corresponding linear equation; The image formed by the points whose coordinates are the solution of the binary linear equation system ax+by=c is the same as that of the linear function y= (-a/b) x+c/b;
3. The solution of binary linear equations axtby=caxtbay= can be regarded as the intersection of two images of linear functions y= (-a/b) xtc/d and Y = (a/b) XTC/D. ..