问题
单项选择题
若正弦序列x（n）=sin（30nπ/120）是周期的，则周期是N=（）。
A.2π
B.4π
C.2
D.8
答案
参考答案：D
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若正弦序列x（n）=sin（30nπ/120）是周期的，则周期是N=（）。
A.2π
B.4π
C.2
D.8
参考答案：D
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