ot 2 A at+ =A0 2 X 0 T x=AcoS(at+), 'v=Ao cos(@t++ 2 a=-Aa cos(at+)vm  A ) 2 π v  A cos(t   cos( ) 2 a  A t  2 an  A 2 π t   mv  v   x y 0 A  t   x  Acos(t ) n a a 