(sin²80°-sin²10°)²+cos²70°的值为多少?

来源：学生作业帮助网编辑：六六作业网时间：2024/12/18 14:33:20

(sin²80°-sin²10°)²+cos²70°的值为多少?(sin²80°-sin²10°)²+cos²70°的值

(sin²80°-sin²10°)²+cos²70°的值为多少?
(sin²80°-sin²10°)²+cos²70°的值为多少?

(sin²80°-sin²10°)²+cos²70°的值为多少?
(sin²80°-sin²10°)²+cos²70°
=(cos²10°-sin²10°)²+cos²70°
=(cos20°)²+cos²70°
=cos²20°+cos²70°
=sin²70°+cos²70°
=1

原式=(cos²10°-sin²10°）²+cos²70°
=cos²20°+cos²70°
=sin²70°+cos²70°
=1