ap dung cong thuc doc lap thoi gian $\Rightarrow $A=4 cmvi van toc co gia tri am $\Rightarrow $ phuong trinh giao dong la:$x=4.\cos (10\sqrt{5}t+\Pi/3)$
ap dung cong thuc doc lap thoi gian $\Rightarrow $A=4 cmvi van toc co gia tri am $\Rightarrow $ phuong trinh giao dong la:$x=4.\cos (10\sqrt{15}t+\Pi/3)$
ap dung cong thuc doc lap thoi gian $\Rightarrow $A=4 cmvi van toc co gia tri am $\Rightarrow $ phuong trinh giao dong la:$x=4.\cos (10\sqrt{5}t+\Pi/3)$