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(tan10°−
3
)sin40°=______．
人气：317 ℃　时间：2020-07-11 11:33:46
解答
(tan10°−
3
)sin40°
=(
sin10°
cos10°
−
3
)sin40°
=
sin10°−
3
cos10°
cos10°
×sin40°
=2
1
2
sin10°− 
3
2
cos10°
cos10°
×sin40°
=2
sin(10°− 60°)
cos10°
×sin40°
=
−2sin50°
cos10°
×sin40°
=
−sin80°
cos10°

=-1．
故答案为：-1．
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