比较大小sin(-10分之4π)与sin(-9分之44π) cos508°与cos(-146°)要写出具体过程,谢谢

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比较大小sin(-10分之4π)与sin(-9分之44π) cos508°与cos(-146°)要写出具体过程,谢谢

①y=sinx在(-π/2,π/2)为增函数
sin(-4π/10)=sin(-2π/5);
sin(-44π/9)=sin(-4π-8π/9)=sin(-8π/9)
=- sin(π-8π/9)=-sinπ/9=sin(-2π/5)
-π/2