... động điều hòa :Cho : 156sin2x tπ=( cm ) ;256cos2x tπ=(cm)Tìm x = x1 + x2 ?HD: 15 56sin 6cos( )2 2 2x t tπ π π= = − (cm)A= 6 2 (cm) ;5 6 2 cos( )2 4x tπ π= ... sin2v A Aπω ω= − = − = -31, 4 ( cm/s )- t = 1( ) 6 sx =10cos( ) 10sin( ) 5 6 2 6 cmπ π π= + = − = −sin( ) cos( ) 6 2 6 v A Aπ π πω ω= − + = −= -27,19cm/s2a xω= − = - 49,29 ... 24cos .0,5 16, 9( )2x cmππ = + = − ÷ 5 224 sin ( 12 )( ) 26, 64 /2 4 2v cm sπ ππ= − = − − =c) 12 24cos( )2x tππ= − = + suy ra : t =2( )3s v = 32 ,6 cm/sBài 4 (SBT...