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问题: 化简

cos50(tan190-√3)

解答:

cos(50)(tan(190)-√3)
=cos(50)(tan(10)-tan(60))
=cos(50)(sin(10)/cos(10)-sin(60)/cos(60))
=cos(50)*[sin(10)cos(60)-sin(60)cos(10)]/[cos(10)cos(60)]
=cos(50)*[-sin(50)]/[cos(10)cos(60)]
=-[sin(100)/2]/[cos(10)cos(60)]
=-cos(10)/[2cos(10)cos(60)]=-1/[2*1/2]=-1