题目

 —Do the two boys have big noses? —____ A. Yes, they are.                                          B. No, they aren’t.  C. No, they have big ones.                           D. Yes, they do. 答案：D函数f(x)的横坐标伸长到原来的两倍,再向左平移个单位,所得到的曲线是y=sinx的图象,试求函数y=f(x)的解析式.