怎么比较cos(3π /5),cos(π /4)的大小?是要根据图像吗?

怎么比较cos(3π /5),cos(π /4)的大小?是要根据图像吗? cos(-5π/6)和cos(-3π/4)比较大小 详细过程谢谢 cos（π/11）cos（2π/11）cos（3π/11）cos（4π/11）cos（5π/11）怎么解 计算：cos（π/5)+cos（2π/5)+cos(3π/5)+cos(4π/5) 求值:cos(π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11) 求值：cos(π/11)-cos(2π/11)+cos(3π/11)-cos(4π/11)+cos(5π/11) cos(π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11) sin7/4 与cos 5/3怎么比较大小 比较大小(1)sin(-π/16)与sin(-π/5) (2)cos(-33/5π)与cos(-13/3π) θ∈(0,π/2),比较cosθ、sin(cosθ)、cos(sinθ)的大小 cos(-3/5π),cos(14/5π),sin(2/5π)比较大小答案是sin(2/5π)>cos(-3/5π)>cos(14/5π) 我觉得有问题 化简cos^8(π/8)+cos^8(3π/8)+cos^8(5π/8)+cos^8(7π/8) cos(α+5π/12)cos(α+π/6)+cos(π/12-α)cos(π/3-α) 化简 cos^2 π/8+cos ^2 3π/8+ cos^2 5π/8+cos^2 7π/8=? 计算cos(a+5π/12)cos(a+π/6)+cos(π/12-a)cos(π/3-a） COS(π/7)+COS(3π/7)+COS(5π/7)化简求值, cos(3π-α)怎么化简 怎么算cos-32π/3