cos(-17/4π)-sin(-17/4π)的值为 ⊙ _ .

问题描述:

cos(-

17
4
π)-sin(-
17
4
π)的值为 ⊙ ___ .

cos(-

17π
4
)-sin(-
17π
4
)=cos
17
4
π+sin
17π
4

=cos(4π+
π
4
)+sin(4π+
π
4
)=cos
π
4
+sin
π
4

=
2
2
+
2
2
=
2

故答案为:
2