10
                     
                   
9
                     
                   
8
                     
                   
7
                     
                   
6
                     
                   
5
                     
                   
4
                     
                   
3
                     
                   
2
                     
                   
1
                     
-20
-19
-18
-17
-16
-15
-14
-13
-12
-11
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
                   
-1
                     
                   
-2
                     
                   
-3
                     
                   
-4
                     
                   
-5
                     
                   
-6
                     
                   
-7
                     
                   
-8
                     
                   
-9
                     
                   
-10
                     
自变量 x     
f(x)=__________     
g(x)=__________     
u(x)=__________     
v(x)=__________