(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：2024/05/29 00:14:22
(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