要得到函数y=sin（
|
∵y=cos2x=sin（
-2x），π 2
∴令f（x）=sin（
-2x），π 2
则f（x+
）=sin[π 12
-2（x+π 2
）]=sin（π 12
-2x），π 3
∴要得到函数y=sin（
-2x）的图象，只需将函数y=cos2x=sin（π 3
-2x）的图象向左平移π 2
个单位．π 12
故选D．
| 任务型阅读：下面是三家电影院星期五的电影海报(Film Poster)。请仔细阅读，然后简要回答问题。 | |||
| |||
| 1. What film can Miss Smith go to see if she is free after 9:05 p.m.? ________________________________. | |||
| 2. Jack and his twenty other classmates are all twelve years old. They have only 100 dollars. Can they go to see the film Titanic? _________________________________. | |||
| 3. If Mrs. White goes to see the film Out of Africa with her husband and son Tom (eleven years old), how much should she pay? _________________________________. | |||
| 4. If a man wants to see the film Titanic, what telephone number should he call? _________________________________. | |||
5. There are fifty-five students in Jack’s class. If all the students in Jack’s class go to see the film Harry Potter, how much should they pay together? ________________________. |