A:一根小于1,另一根大于3
B:一根小于-2,另一根大于2
C:两根都小于0
D:两根都大于2
With the help of the teacher, he decided _______ in class.
要得到函数y=cos(3x﹣π4)的图象,只需将函数y=sin3x的图象( )