physics有關optic and waves的問題

Question

The displacement x of a simple harmonic oscillator is given by the equation x = 10cos(10t + 1) m, where t is the time in s. What is the amplitude of the oscillation in m? Enter your answer with a rounding error of less than 10%.

Answer 1

since the values of cosine function lie between -1 and 1
so -1<1
-10<10cos(10t+1)<10
the amplitude is indeed 10 m

Answer 2

The amplitude is 10 m.