gaokao 2015 Q4

gaokao · China · national-II-arts Vectors Introduction & 2D Dot Product Computation
4. Given $\vec { a } = ( 0 , - 1 ) , \vec { b } = ( - 1,2 )$, then $( 2 \vec { a } + \vec { b } ) \cdot \vec { a } =$
A. $- 1$
B. $0$
C. $1$
D. $2$
4. Given $\vec { a } = ( 0 , - 1 ) , \vec { b } = ( - 1,2 )$, then $( 2 \vec { a } + \vec { b } ) \cdot \vec { a } =$\\
A. $- 1$\\
B. $0$\\
C. $1$\\
D. $2$