问题标题:
求sin6度乘以cos24度乘以sin78度乘以cos48度得值
问题描述:
求sin6度乘以cos24度乘以sin78度乘以cos48度得值
段星辉回答:
原式=sin(6)cos(12)cos(24)cos(48)=sin(6)cos(6)cos(12)cos(24)cos(48)/cos(6)
=0.5sin(12)cos(12)cos(24)cos(48)/cos(6)=……=(1/16)sin(96)/cos(6)=(1/16)cos(6)/cos(6)=1/16
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