解:∵│sin(5/x)│≤1
∴sin(5/x)是有界函数
==>lim(x->0)[xsin(5/x)]=0
故lim(x->0)[((3x^3+5x)/(5x²+3))sin(5/x)]
=lim(x->0)[((3x²+5)/(5x²+3))(xsin(5/x))]
=lim(x->0)[(3x²+5)/(5x²+3)]*lim(x->0)[xsin(5/x)]
=[(0+5)/(0+3)]*0
=0。