8sin870°•cos(-660°)•cot(-355°)•tan(-175°)的值是( )A.2B.-2C.12D.-12
题型:单选题难度:一般来源:不详
8sin870°•cos(-660°)•cot(-355°)•tan(-175°)的值是( ) |
答案
因为8sin870°•cos(-660°)•cot(-355°)•tan(-175°) =8sin(720°+150°)•cos(660°)•cot(355°)•tan(175°) =8sin150°•cos(720°-60°)•cot(360°-5°)•tan(180°-5°) =-4cos60°•cot(-5°)•tan5° =2•cot5°•tan5° =2. 故选A. |
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