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设是直线的倾斜角,向量,
若⊥,则直线的斜率是( )
A.1 B. C. D.
设是直线的倾斜角,向量,若,则直线的斜率是( )
A. B. C. D.
设是直线的倾斜角,向量,若⊥,则直线的斜率是( )