摘要:在同一平面内.已知..且.若..则的面积等于( ) A. B. C. 1 D. 2
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在同一平面内,已知
=(cosα,sinα),
=(cosβ,sinβ),且
•
=0.若
′=(cosα,2sinα),
′=(cosβ,2sinβ),则△A'OB'的面积等于( )
| OA |
| OB |
| OA |
| OB |
| OA |
| OB |
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| OA |
| OB |
| OA |
| OB |
| OA |
| OB |