(sin²80°-sin²10°)²+cos²70°的值为多少?

来源：学生作业学帮网编辑：学帮网时间：2024/07/04 10:16:33

(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