函数y=sin(3x-π/2)-1的图像的一条对称轴方程是 A.x=π/6 B.x=π/3 C.x=π/2 D.x=3π/2
问题描述:
函数y=sin(3x-π/2)-1的图像的一条对称轴方程是 A.x=π/6 B.x=π/3 C.x=π/2 D.x=3π/2
答
y=sin(3x-π/2)-1
=-cos3x-1
答案:B.x=π/3
答
即sin(3x-π/2)=±1
3x-π/2=kπ-π/2
x=kπ/3
选B
答
y=sin(3x-π/2)-1
3x-π/2=2kπ+π/2
3x=2kπ+π
x=2kπ+π/3
当k=0 x=π/3是其中一条对称轴
所以选B
答
A