将函数y=cos(2x+2π3)的图象向左平移π2个单位长度,所得图象的函数解析式为( ) A.y=−sin(2x+2π3) B.y=−cos(2x+2π3) C.y=cos(2x+2π3) D.y=sin(2x+2π3)
问题描述:
将函数y=cos(2x+
)的图象向左平移2π 3
个单位长度,所得图象的函数解析式为( )π 2
A. y=−sin(2x+
)2π 3
B. y=−cos(2x+
)2π 3
C. y=cos(2x+
)2π 3
D. y=sin(2x+
) 2π 3
答
y=cos(2x+
)2π 3
y=cos[2(x+图象向左平移
个单位长度π 2
)+π 2
]=cos(2x+π+2π 3
)=-cos(2x+2π 3
).2π 3
故选B.