1. Hàm \(y=cos\left(3x+\dfrac{\pi}{3}\right)\) có chu kì \(T=\dfrac{2\pi}{\left|3\right|}=\dfrac{2\pi}{3}\)
2. \(y=4sin2x.cos3x=2sin5x-2sinx\)
Hàm \(y=2sin5x\) có chu kì \(T_1=\dfrac{2\pi}{5}\)
Hàm \(y=2sinx\) có chu kì \(T_2=2\pi\)
\(\Rightarrow y=2sin5x-2sinx\) có chu kì \(T=BCNN\left(\dfrac{2\pi}{5};2\pi\right)=2\pi\)
3.
Hàm \(y=cot\left(x+\dfrac{\pi}{4}\right)\) có chu kì \(T=\pi\)
5.
Hàm \(y=tan\left(\dfrac{\pi}{3}+\dfrac{x}{5}\right)\) có chu kì \(T=\dfrac{\pi}{\left|\dfrac{1}{5}\right|}=5\pi\)