求複數z=tanθ-i(π/2

題目：

求複數z=tanθ-i(π/2

解答：

z=tanθ-i
=-cot(π/2+θ)-i
=-1/sin(π/2+θ)(cos(π/2+θ）+isin（π/2+θ))
=1/sin(π/2+θ)(cos(π+π/2+θ）+isin（π+π/2+θ))
=1/sin(π/2+θ)(cos(θ-π/2）+isin（θ-π/2))
再問： π/2