8sin870°•cos(-660°)•cot(-355°)•tan(-175°)的值是(  ) A.2 B.-2 C.

8sin870°•cos(-660°)•cot(-355°)•tan(-175°)的值是(  )
A.2 B.-2 C.
1
2
D. -
1
2
0Hyeah 1年前 已收到1个回答 举报

yetoyato 幼苗

共回答了15个问题采纳率:93.3% 举报

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.

1年前

1
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