化简(1)cos315°+sin(-30)°+sin225°+cos480°(2)1+2sin290°cos430°si
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/04 14:44:39
化简
(1)cos315°+sin(-30)°+sin225°+cos480°
(2)
(1)cos315°+sin(-30)°+sin225°+cos480°
(2)
| ||
sin250°+cos790° |
(1)cos315°+sin(-30)°+sin225°+cos480°
=cos(360°-45°)-sin30°+sin(180°+45°)+cos(360°+120°)
=cos(-45°)-sin30°-sin45°+cos120°
=cos45°-sin30°-sin45°-cos60°
=
2
2−
1
2−
2
2−
1
2=-1.
(2)原式=
1+2sin(360°−70°)cos(360°+70°)
sin(180°+70°)+cos(720°+70°)
=
1−2sin70°cos70°
−sin70°+cos70°=
(sin70°−cos70°)2
cos70°−sin70°=
|sin70°−cos70°|
cos70°−sin70°
=
sin70°−cos70°
cos70°−sin70°=-1.
=cos(360°-45°)-sin30°+sin(180°+45°)+cos(360°+120°)
=cos(-45°)-sin30°-sin45°+cos120°
=cos45°-sin30°-sin45°-cos60°
=
2
2−
1
2−
2
2−
1
2=-1.
(2)原式=
1+2sin(360°−70°)cos(360°+70°)
sin(180°+70°)+cos(720°+70°)
=
1−2sin70°cos70°
−sin70°+cos70°=
(sin70°−cos70°)2
cos70°−sin70°=
|sin70°−cos70°|
cos70°−sin70°
=
sin70°−cos70°
cos70°−sin70°=-1.
1.√1+2sin650°cos430°/sin290°+cos790°
化简:[根号(1-2sin290°cos110°)]/(sin250°+sin20°)
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