%8-18  ʹ  ƾ״ͼΡ

>> % óڻƾ״ͼ
>> % ûyֵstemv(y)ɵн
>> y=rand(20,1);
>> stem(y)
>>

>> % óڻƾ״ͼ
>> % ûxyֵstem(x,y,s)ɵн
>> % ｫsΪbͼΪɫ
>> x=-20:0.25:20;
>> y=x.^2-2.*x+10;
>> stem(x,y,'b')
>>
