L=2A suy ra A= L/2 = 10 cm

Gốc thời gian lúc vật đi qua vị trí cân bằng theo chiều âm

suy ra góc ban đầu = \(-\frac{\pi}{2}\)

\(\omega=\frac{2\pi}{T}\) = \(\pi\)

suy ra x= 10\(\cos\left(\pi t-\frac{\pi}{2}\right)\)

In my opinion, parents should strictly limit teenagers' screen time for some reasons. Firstly, teenagers have little time left for homework, they spend too much time on screen time such as watching online videos, checking social media, or playing computer games. This problem has bad effects on learning of teenagers like bad marks, ete.. Moreover, too much screen time is bad for teenager's health. Too much screen time can damage eyesight, reduce sleep time, and cause weight gain. In conclusion, the problems have negative influences for age of teenagers so parents should strictly limit teenager's screen time.