（1）化简f（α）f(α)=sin(α-π/2)cos(3π/2+α)tan(π-α)除以tan(-α-π）sin(-α-π）=-cosαsinα(-tanα)÷[(-tanα)sinα]=-cosα（2）若cos（α-3π/2)=1/5,求f（α）的值cos（α-3π/2)=cos（π/2+α)=－s...