cos(-17/4π)-sin(-17/4π)的值为 ⊙ _ .
问题描述:
cos(-
π)-sin(-17 4
π)的值为 ⊙ ___ .17 4
答
cos(-
)-sin(-17π 4
)=cos17π 4
π+sin17 4
17π 4
=cos(4π+
)+sin(4π+π 4
)=cosπ 4
+sinπ 4
π 4
=
+
2
2
=
2
2
.
2
故答案为:
2