已知cos(π+α)=-5⼀13,3π⼀2<α<2π,求sin(2π-α)的䀁

2025-04-09 07:43:56
推荐回答(1个)
回答1:

由cos(π+α)=-cosa=-5/13,即cosa=5/13,
又3π/2<α<2π,得sinα=-12/13
则sin(2π-α)=sin(-α)=-sinα=12/13