> 其他 >
设α为锐角,若cos(α+
π
6
)=
3
5
,则sin(α-
π
12
)=______.
人气:396 ℃ 时间:2020-01-28 02:35:47
解答
∵α为锐角,cos(α+
π
6
)=
3
5
为正数,
∴α+
π
6
是锐角,sin(α+
π
6
)=
4
5

∴sin(α-
π
12
)=sin[(α+
π
6
)-
π
4
]
=sin(α+
π
6
)cos
π
4
-cos(α+
π
6
)sin
π
4

=
4
5
×
2
2
-
3
5
×
2
2
=
2
10

故答案为:
2
10
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