[matlab] matlab lesson 2 - preliminary drawing

One . Basic knowledge of drawing

1. Image introduction ：

2. Summary of knowledge points ：


【 Add ： It can be used get( ) Quickly obtain the specified identification code handle】

picture (a):

picture (b):

attach ： Line style sheet

！！！ Knowledge points note file access point here ！！！

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Two . The operation sample

【 Example 1 】plot(x,y) Draw a scatter line chart
The image displayed ：

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【 Example 2 】plot(y) Description function

The image displayed ：

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【 Example 3 】 Use title(),legend(),lable() Draw a beautiful chart

* The wrong sample ： Misuse plot.

This reminds us plot The correct use of ：

① How to （x,y） At the same time, it is placed in one plot Inside .
At this time x and y Parameters can be shared t, It can also be a functional relationship with each other .
②y1,y2,y3,…,yn All are x Function of , If only incoming y, Once only in plot Write a .

Write it correctly ：

The effect is as follows :

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【 Example 4 】 Application set Instruction to modify axis Parameters

Display trigonometric function image , We certainly hope that the abscissa is π Multiple , The ordinate is [-1,1] The range of .
Use set This can be achieved , Let's optimize “ Example 3 ” Image in ：

The effect is this ：

< Problem finding >：
① We see that the abscissa division does become π 了 , But it's in decimal form , Can't show π Symbol .
② and , The image above is obviously inaccurate , There is a numerical deviation .
therefore , Let's make improvements ：

The effect achieved the expectation ：

meanwhile , We have also learned a lesson ：

When depicting images related to trigonometric functions , The step size of the independent variable is π Multiple .

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【 Example 5 】 Use set modify “ Tracing point ” style , Make the chart more like a line chart

Problem procedure ：

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【 Example 6 】 Use subplot Generate multiple images


Of course, we can also do this