题目内容
化简
=______．
| ||
| sin250°+cos790° |
原式=
=
=
=
=-1．
故答案为：-1
| ||
| sin(180°+70°)+cos(720°+70°) |
=
| ||
| -sin70°+cos70° |
| |sin70°-cos70°| |
| -sin70°+cos70° |
| sin70°-cos70° |
| -(sin70°-cos70°) |
故答案为：-1
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