题目

函数y=sinx-cosx在x∈［0,］的最小值为A.-1                  B.-                C.0                    D.-2 答案：答案:A解析：函数y=sinx-cosx=2sin(x),又x∈［0,］,∴x∈［,］.当x=时,ymin=2·sin()=-1.—_______ did you buy the new bag? 　 —Last Monday. [     ]A. Where　B. How　C. When　D. Who