用诱导公式求下列三角函数值:(1) sin(- 17π 6 ) (2) cos(- 13π 4 )

用诱导公式求下列三角函数值:(1) sin(- 17π 6 ) (2) cos(- 13π 4 ) .
2024-11-24 03:31:36
推荐回答(1个)
回答1:

(1)sin(-
17π
6
)=sin[-4π+(π+
π
6
)]
=sin(π+
π
6
)=-sin
π
6
=-
1
2

(2)cos(-
13π
4
)=cos
13π
4
=cos[2π+(π+
π
4
)]
=cos(π+
π
4
)=-cos
π
4
=-
2
2