把下列各角度化成0到2π的角加上2kπ（k∈Z）的形式

题目

把下列各角度化成0到2π的角加上2kπ（k∈Z）的形式
(1) -25/6π (2)-5π (3)-45° (4)400°

答案

(1) -25π/6
=24π/6-π/6
=-4π-π/6
=-6π+2π-π/6
=-6π+11π/6
(2)-5π
=-6π+π
(3)-45°
=-π/4
=-2π+7π/4
(4)400°
=400/180 *π
=2π+2π/9