化简 {sin(π+α)cos(α-2π)tan9π/4}/sin(-α)sin(7π/2+α)过程_数学解答

化简 {sin(π+α)cos(α-2π)tan9π/4}/sin(-α)sin(7π/2+α)
过程

人气：157 ℃　时间：2020-06-07 17:04:37

解答

[sin(π+a)cos(a-2π)tan9π/4]/sin(-a)sin(7π/2+a)
=[-sinacosatan(π/4+2π)]/-sinasin(3π/2+2π+a)
=(-sinacosa)/-sina(-cosa)
=-1