Functional image drawing:
First of all, we should distinguish what kind of function it is, such as proportional function, inverse proportional function, linear function, quadratic function, trigonometric function, logarithmic function, exponential function and so on. Then find the key point, if it is a linear function, find two points, if it is a quadratic function, first find the symmetry axis, vertex coordinates and the intersection with the coordinate axis, and so on.
If it is a trigonometric function, such as sine and cosine functions, use the five-point method to draw. If it is a logarithmic function and an exponential function, first distinguish whether its "bottom" is greater than 1 or less than 1.
Exercise and Graphics: Calculate the intersection coordinates of the function image with the Y axis and the X axis through the following three steps (1) (2) Drawing points; (3) Connecting lines can make images of linear functions-straight lines.
High school math. How to draw this function image A: I can't see the function, so I can't say how to draw the specific image. They are all images of algebraic function, trigonometric function, exponential function, logarithmic function and inverse function.
The basic point of painting is to master the characteristics of the image and then start painting, so there is no problem. For example, draw a circle, grasp the center and radius, and grasp these two characteristics, and you can draw it. Such as parabola; Vertex, opening direction, intersecting two axes. Draw its characteristics and this picture will come out. Draw the direction of other irrelevant things.
Step-by-step drawing of quadratic function image
quadratic function
Steps of image: The five-point method is to select five extremely important points, namely, the vertex, the intersection with the X axis, the intersection with the Y axis and the relationship between them.
axis of symmetry
Symmetrical points, and then draw according to these five points.
Drawing method of quadratic function
Five-point method
Five-point sketch, also known as five-point drawing, is a common drawing method in quadratic function.
Note: Although it is a sketch, it is by no means a sketch.
Five points in the five-point sketch method are extremely important, namely, the vertex, the intersection with the X axis, the intersection with the Y axis and their symmetrical points about the axis of symmetry.
The formal examination also uses this method to preliminarily determine the image. But the requirement of the formal examination is to list the grids, take X and Y, and then determine the overall image. You can use the five-point method in the formal examination.
Point tracing method
1 list
Take the vertex first and draw the axis of symmetry with a dotted line. Take two intersections with X axis (if any), Y axis intersection and its symmetry point (if any), and the other two points and their symmetry points. In principle, the difference between adjacent x's is equal, but the point far from the vertex can reduce the difference appropriately.
2. Draw the function image according to the table data.
Quadratic function root formula
Derive the solution of ax_+bx+c=0.
Transposition, ax_+bx=-c
One on each side, and then formulated,
x_+(b/a)x+(b/2a)_=-c/a+(b/2a)_
[x+b/(2a)]_=[b_-4ac]/(2a)_
Open square roots on both sides and get the solution.
x=[-b √(b2-4ac)]/(2a)