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求值:(tan10°-
3
)sin40°.
人气:268 ℃ 时间:2020-05-21 12:27:09
解答
(tan10°-
3
)sin40°
=
sin10°
3
cos10°
cos10°
•sin40°

=
−2sin50°cos50°
cos10°

=-
sin100°
cos10°

=-
cos10°
cos10°

=-1.
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