化简:[sin(﹣α)cos(π-α)]∕[tan(π+α)sin﹙3π/2+α)]

来源:学生作业学帮网 编辑:学帮网 时间:2024/06/05 11:12:44

化简:[sin(﹣α)cos(π-α)]∕[tan(π+α)sin﹙3π/2+α)]

[sin(﹣α)cos(π-α)]∕[tan(π+α)sin﹙3π/2+α)]
=[(﹣sinα)(-cosα)]∕[tanα﹙-cosα)]
=-sinαcosα∕[tanαcosα]
=-sinα/tanα
=-cosα

[sin(﹣α)cos(π-α)]∕[tan(π+α)sin﹙3π/2+α)]
=[(-sinα)*(-cosα)]∕[tanα*cosα]
=cosα