-5,3,5都是弧度sin(-5)=-sin5∵3π/2<5<2π∴sin5<0,sin(-5)>0∵π/2<3<π∴sin3>0sin(-5)=sin(5-π)∵π/2<5-π<π5-π<3∴sin(5-π)>sin3因此，sin(-5)>sin3>sin5
