设a=sin5π⼀7,b=cos(-2π⼀7),c=tan9π⼀7,则a,b,c从大到小的顺序排列是?

2024-12-01 08:42:39
推荐回答(1个)
回答1:

a=sin5π/7=sin2π/7
b=cos(-2π/7)=cos2π/7
c=tan9π/7=tan2π/7
2π/7属于(π/4,π/2)
sin2π/7>cos2π/7 tan2π/7=sin2π/7/cos2π/7>1
tan2π/7>sin2π/7>cos2π/7