如何判断asint-bsin3t是否为周期函数

asint-bsin3t

用最小公倍数法：

asint：最小正周期2π

bsin3t：最小正周期2π/3

∴最小正周期是2π

f(t)=asint-bsin3t

f(t+2π)=aasin(t+2π)-bsin3(t+2π)

=asin(t+2π)-bsin(3t+6π)

=asint-bsin3t

=f(t)