比较sin2π/5,cos5π/6,tan7π/5的大小(详细过程)

问题描述:

比较sin2π/5,cos5π/6,tan7π/5的大小(详细过程)

sin2π/5=sin72
cos5π/6= cos75=sin15 故sin2π/5 >cos5π/6
tan7π/5=tan(7π/5 -π)=tan2π/5=(sin2π/5) / (cos2π/5),
而 0所以
tan7π/5 > sin2π/5 >cos5π/6