问题 填空题
化简
1-2sin10°cos10°
sin170°-
1-sin2170°
=______.
答案

1-2sin10°cos10°
sin170°-
1-sin2170°

=

(sin10°-cos10°)2
sin10°-
cos210°

=

cos10°-sin10°
sin10°-cos10°

=-1.

故答案为:-1.

单项选择题
单项选择题