Everything in our school since 2009. Now, it very modern.
A：is changed; is looked
B：is changed; looks
C：has changed; is looked
D：has changed; looks
- _________are his football clothes?
- Under the bed.
甲、乙两台机床同时加工直径为10mm的同种规格零件，为了检查两台机床加工零件的稳定性，质检员从两台机床的产品中各抽取5件进行检测，结果如下（单位：mm）：
甲
10
9.8
10.2
乙
9.9
10.1
（1）分别求出这两台机床所加工零件直径的平均数和方差；
（2）根据所学的统计知识，你认为哪一台机床生产零件的稳定性更好一些，说明理由．
若cos2αsinκ-π4=-22，则cosα+sinα的值为（ ）
