sin(－54π/7)【大于】sin(－63π/8)
sin(－54π/7)=sin(2π/7)；sin(－63π/8)=sin(π/8)
因为：0怎么计算sin(－54π/7)=sin[(－54π/7)＋8π]=sin(2π/7)sin(－63π/8)=sin[(－63π/8)＋8π]=sin(π/8)而：0<π/8<2π/7<π/2则：sin(2π/7)>sin(π/8)即：sin(－54π/7)>sin(－63π/8)