Giúp tớ nha tớ tham khảo

$\begin{cases} A = 4 (cm)\\T=\frac{t}{N} = \frac{10}{20} = \frac{1}{2} (s) => \omega = \frac{2\pi}{T} = 4\pi (rad) \\\begin{cases} t = 0 (s) => x = A = 5 (cm)\\\text{chiều âm} \end{cases} => \varphi = 0 (rad) \end{cases}$

`a)` `x = 5cos (4\pi.t) (cm)`

`b)` `|v_{max}| = \omega . A = 4\pi . 5 = 20\pi` `\text{(cm/s)}`

`c)` `a_{max} = \omega^{2} . A = 80\pi^{2}`

` Vậy ` _____________________________________________________

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