(2sin5°-cos25°)\(cos65°)=?( 根号下1-2sin10°cos10°)\(根号下1-cos^2170°-cos350°)=?
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/02 07:04:51
![(2sin5°-cos25°)\(cos65°)=?( 根号下1-2sin10°cos10°)\(根号下1-cos^2170°-cos350°)=?](/uploads/image/z/3810980-20-0.jpg?t=%282sin5%C2%B0-cos25%C2%B0%29%5C%28cos65%C2%B0%29%3D%3F%EF%BC%88+%E6%A0%B9%E5%8F%B7%E4%B8%8B1-2sin10%C2%B0cos10%C2%B0%29%5C%28%E6%A0%B9%E5%8F%B7%E4%B8%8B1-cos%5E2170%C2%B0-cos350%C2%B0%29%3D%3F)
(2sin5°-cos25°)\(cos65°)=?( 根号下1-2sin10°cos10°)\(根号下1-cos^2170°-cos350°)=?
(2sin5°-cos25°)\(cos65°)=?( 根号下1-2sin10°cos10°)\(根号下1-cos^2170°-cos350°)=?
(2sin5°-cos25°)\(cos65°)=?( 根号下1-2sin10°cos10°)\(根号下1-cos^2170°-cos350°)=?
(2sin5°-cos25°)\(cos65°)
=(2sin5°-cos(30-5)°)\(cos65°)
=(2sin5°-(√3/2cos5°+1/2sin5°)\(cos65°)
=(3/2sin5°-√3/2cos5°)/(cos65°)
=√3(√3/2sin5°-1/2cos5°)/(cos65°)
=-√3(sin(30-5))/(cos65°)
=-√3