求值sin42°-cos12°+sin54°
来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:数学作业 时间:2024/07/10 07:39:45
求值sin42°-cos12°+sin54°
![求值sin42°-cos12°+sin54°](/uploads/image/z/18436102-70-2.jpg?t=%E6%B1%82%E5%80%BCsin42%C2%B0-cos12%C2%B0%2Bsin54%C2%B0)
sin42°-cos12°+sin54°
=sin42°-sin78°+sin54°
=-2cos60°sin18°+sin54°
=sin54°-sin18°
=2cos36°sin18°
=2cos36°sin18°sin36°/sin36°
=sin18°sin72°/sin36°
=2sin18°cos18°/2sin36°
=sin36°/2sin36°
=1/2
=sin42°-sin78°+sin54°
=-2cos60°sin18°+sin54°
=sin54°-sin18°
=2cos36°sin18°
=2cos36°sin18°sin36°/sin36°
=sin18°sin72°/sin36°
=2sin18°cos18°/2sin36°
=sin36°/2sin36°
=1/2
一道三角函数化简求值sin42度-cos12度+sin54度
三角恒等变换解答题求sin42-cos12+sin54的值求cos2pai/7+cos4pai/7+cos6pai/7的
化简sin12°×sin48°×sin54°?
求值:sin12°cos18°+cos12°sin18°=( )
求值:(根号3乘以tan12°-3)/【sin12°(4cos12°-2)】
求值:(tan12°-根号3)/(sin12°(4cos12°-2))
求值:(√3tan12°-3)/(4(cos12°)^2-2)sin12°
cos54°-sin54°化为积的形式是
sin6°sin42°sin66°sin78°=?
化简:sin48°×sin57°—sin42°sin33°
sin6°sin42°sin66°sin78°=
(tan12°-根号3)/【(4*cos12°*cos12°)*sin12°