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

=(sin6*cos6*cos24*sin78*cos48)/cos6 =(sin12*cos24*sin78*cos48)/2cos6 =(sin12*cos24*cos12*cos8)/2cos6 =(sin48*cos48)/8cos6 =sin96/(16cos6) =cos(90-96)/16cos6 =1/16

该求解方式为:在原式上添加COS6度 然后除以COS6度即可
答案为:16分之一

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

sin6度乘以cos24度乘以sin78度乘以cos48度查表相乘即可