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在平面直角坐标系中,已知向量=(3,-1),=(2,1),且•=7,那么•等于A.2或-2...
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在平面直角坐标系中,已知向量
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABYAAAAWCAYAAADEtGw7AAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAQZJREFU
SEvVVMENwyAM9EjZp1swBEuwQwdgDqTswBJXwBDAcapKJVIbKY8Q+7g7HxCWPDvsw2IfsGgJbgbZ
LbbH84Cj9GDdu8FW2vcxXmPFnR4Lhuus+AHgAO/jxCM4JUHGY67ilgsrIrwhGAGcG6I3IBfqhgEu
x/X47jxU4NKcGs71vOG4XlR8BBw9nE82CIDCJf0z5ND4MgEDRZi0IkkrnmWJ54ampJ1UzapmxmRF
cJWNYMbFwoZSo89hGp5kQ4NkzYa8xinp1owRYsbF1yE0wYFEjOY0dAWyrluRJWkg09pFGtTk1Bzz
INqgGKBfo0lmZq9erXoa1OGtuenenrzvt/i/2+0FGtCyc9cjZOUAAAAASUVORK5CYII=
)
=(3,-1),
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAwAAAAWCAYAAAD0OH0aAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAKlJREFU
OE/dU+0NhCAMZST3cYsOwRLs4ACdg4QdWOLZUjz1FNHE+3NNTCC+rxZwuKwEP3qkDcZdE+Rv8hjG
6QNzUuh/A3y1ee7wfg9fiv1I/0mICPXwQtQOM5jsMG2/rzolJQXEAiZwFhoTSBenhMwgYnAw8OLS
dFC1XYQqcNQHJJJl3qq14qi3k7Alzqq29BHBZz0c1FSgTE2H0JxS9xmtD+g+1JC/v60zWobH+S+C
TdAAAAAASUVORK5CYII=
)
=(2,1),且
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAwAAAAWCAYAAAD0OH0aAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAKlJREFU
OE/dU+0NhCAMZST3cYsOwRLs4ACdg4QdWOLZUjz1FNHE+3NNTCC+rxZwuKwEP3qkDcZdE+Rv8hjG
6QNzUuh/A3y1ee7wfg9fiv1I/0mICPXwQtQOM5jsMG2/rzolJQXEAiZwFhoTSBenhMwgYnAw8OLS
dFC1XYQqcNQHJJJl3qq14qi3k7Alzqq29BHBZz0c1FSgTE2H0JxS9xmtD+g+1JC/v60zWobH+S+C
TdAAAAAASUVORK5CYII=
)
•
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABcAAAAWCAYAAAArdgcFAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAQZJREFU
SEvdVIkNwyAMZKTsky0YgiXYoQN4DqTswBKuzZNiQxqpBakqUhTJIufz3cUGp50D3e7waPDMNGwG
Ohxu++OENHRw7rOhK/TXMp8ny2rNFdO5svwIeECAOLYkeJEwH+ga1dL7PucRwRq0HXiuG+OxxQme
axb19aHmEWxiJpkUYAvYzxPQq4Y8QA8eAT2QJMSwBc8Ne3ZZBWpM3+ijwIlBYsZMWqDCWot685MI
8OCLlsTeijG52ciD9+gneNX5tWca01KzT8GTzo1NHDVhXGZuLmQJMDKZDWVWKgFpCp2Kkm0Zz+zF
lRVl5Vbzao7rGpZ5TkTEir5KT/biL3fL95t+qSxPwMof5dnDJEsAAAAASUVORK5CYII=
)
=7,那么
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAwAAAAWCAYAAAD0OH0aAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAKlJREFU
OE/dU+0NhCAMZST3cYsOwRLs4ACdg4QdWOLZUjz1FNHE+3NNTCC+rxZwuKwEP3qkDcZdE+Rv8hjG
6QNzUuh/A3y1ee7wfg9fiv1I/0mICPXwQtQOM5jsMG2/rzolJQXEAiZwFhoTSBenhMwgYnAw8OLS
dFC1XYQqcNQHJJJl3qq14qi3k7Alzqq29BHBZz0c1FSgTE2H0JxS9xmtD+g+1JC/v60zWobH+S+C
TdAAAAAASUVORK5CYII=
)
•
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABcAAAAWCAYAAAArdgcFAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAQRJREFU
SEvdlIEJxCAMRR2p+3QLh3AJd7gBMofgDi6RUxM0sUrvwHJwheOo6M/Py7cGtz0R3ekwCj2zTbsI
RYfH+WqSJj+493egY/vPOt+H5Wnmg9O9WH4iHvwkNRYwzYYSvEqYD3lTXqv/q5wnsGjajoC+xFSd
SAi2mPAodciYRRicCOZ0UGrVQ22BhafdFCO6YGmgiydAKzbULoSb8V0DyIVhYCLF6XDnblWP7HqE
enNJ2PmApHZhsBcg/rrg/fUj8QFJWaIhMcdLsXvhxlynpFajVLThzZLTCwSYRzY7X6QkY1CIOduz
WaxGsfjkXjPb8cnLttjHTf3Bt+Wz+X+361Esb3r7/siOtn2JAAAAAElFTkSuQmCC
)
等于( )
A.2或-2
B.2
C.-2
D.0
相关试题
-
在平面直角坐标系中,已知向量
=(3,-1),
=(2,1),且
•
=7,那么
•
等于( )
A.2或-2
B.2
C.-2
D.0
-
在平面直角坐标系中,已知向量
,且
,那么
=( )
A.2
B.-2
C.2或-2
D.0
-
在平面直角坐标系中,已知向量
,且
,那么
=( )
A.2
B.-2
C.2或-2
D.0
-
在平面直角坐标系中,已知向量
,且
,那么
=( )
A.2
B.-2
C.2或-2
D.0
-
在平面直角坐标系中,已知向量
,且
,那么
=( )
A.2
B.-2
C.2或-2
D.0
-
已知平面向量
、
的夹角为60°,则
=(
,1),|
|=1,则|
+2
|═( )
A.2
B.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA8AAAASCAYAAACEnoQPAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAACpSURBVDhPzZI7EoUgDEWzLoosh96dUGchtC7E
gqVcCTyf8nEEKzNjk8nxnmQgdIqIMPTdwb1+3aNvw+vS3mBZgWftIJA4eFaAMEPCEBwQ5y6sgFlS
7zm5umgQBmvsPHwqz8Nx/0N5Gr4qZ9jb31O0/+30abZVKifYe5/mnCEYt+VD9OBKudROBjm9B9fK
zc42Jmp6X7tdpFhucwZk3DtY/63pr5IPsVF4B86Vo9xzwCtAAAAAAElFTkSuQmCC
)
C.2![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA8AAAASCAYAAACEnoQPAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAC0SURBVDhPzZNNDsAQEIXnXBaOY+8m1g5i6yBd
zFFe/bY0pGpViUTEN+/NA2EwiAhLcwaP9p979HOYLWTNQfvL7IJtDy0tOCFhHYpU/h1mLmAW9PoL
3CbqNeib7Vsx3f0OnEqU4KTNCbz3/HgIbCWoBEhwqjxFdV9BsDcdTd/knEvnjCAIc2Q7U5hh5Sjt
5CCrd3BUaj5Kk1ffswqHovpcuW+ma+4wAiTMHhzrRvUt5WpqFT4BvDKYovKwNAUAAAAASUVORK5C
YII=
)
D.2
-
已知平面向量
、
的夹角为60°,则
=(
,1),|
|=1,则|
+2
|═( )
A.2
B.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA8AAAASCAYAAACEnoQPAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAACpSURBVDhPzZI7EoUgDEWzLoosh96dUGchtC7E
gqVcCTyf8nEEKzNjk8nxnmQgdIqIMPTdwb1+3aNvw+vS3mBZgWftIJA4eFaAMEPCEBwQ5y6sgFlS
7zm5umgQBmvsPHwqz8Nx/0N5Gr4qZ9jb31O0/+30abZVKifYe5/mnCEYt+VD9OBKudROBjm9B9fK
zc42Jmp6X7tdpFhucwZk3DtY/63pr5IPsVF4B86Vo9xzwCtAAAAAAElFTkSuQmCC
)
C.2![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA8AAAASCAYAAACEnoQPAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAC0SURBVDhPzZNNDsAQEIXnXBaOY+8m1g5i6yBd
zFFe/bY0pGpViUTEN+/NA2EwiAhLcwaP9p979HOYLWTNQfvL7IJtDy0tOCFhHYpU/h1mLmAW9PoL
3CbqNeib7Vsx3f0OnEqU4KTNCbz3/HgIbCWoBEhwqjxFdV9BsDcdTd/knEvnjCAIc2Q7U5hh5Sjt
5CCrd3BUaj5Kk1ffswqHovpcuW+ma+4wAiTMHhzrRvUt5WpqFT4BvDKYovKwNAUAAAAASUVORK5C
YII=
)
D.2
-
已知平面向量
、
的夹角为60°,则
=(
,1),|
|=1,则|
+2
|═( )
A.2
B.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA8AAAASCAYAAACEnoQPAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAALBJREFU
OE/Nk90NhSAMRmEj9mGLDsES7sAAncPEHViitnD9oTZReLpNfJD05Dut6InLqfLe6yP7XWBd3Gkd
P/v+G14XJ3vpnmXlXb1qFyTkxqsKIQBh+QQX4r4biwSA9ew9WakVBAKJHYcv5XGY5z+Uh+G7coNz
/H2CeE5n37BeucI55wql4CikrS3Cup5KudeuBi3dgrXyY+bIiZI+9WNsKZALaQ4WFUmfSj7W/RXe
AUhJkM3kgOb0AAAAAElFTkSuQmCC
)
C.2![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA8AAAASCAYAAACEnoQPAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAALtJREFU
OE/Nk9sVhCAMRENH9EMXFEET9EAB1ME59pAmsgmPFRF15Wv5UuQymUlUxAuGpZQat+bvAo+LT862
z+f+HMZIlq2IHfDpW+zU3NFzIm8jYUb4mS9o/DOMWMEimPwbuE80+bdl74oLnjvpGpyNJYFnz8Mg
YLQENUCgYEoLwOwtuJuwzjeEEDLkNJB2WynnEkaKdpZ2rqCoH2BRagPS9fjk2fBHUV/6MTanCbRb
g6UUUV9SbnH/Cn8A/r2EUaEPy7EAAAAASUVORK5CYII=
)
D.2
-
已知平面向量
、
的夹角为60°,则
=(
,1),|
|=1,则|
+2
|═( )
A.2
B.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA8AAAASCAYAAACEnoQPAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAALBJREFU
OE/Nk90NhSAMRmEj9mGLDsES7sAAncPEHViitnD9oTZReLpNfJD05Dut6InLqfLe6yP7XWBd3Gkd
P/v+G14XJ3vpnmXlXb1qFyTkxqsKIQBh+QQX4r4biwSA9ew9WakVBAKJHYcv5XGY5z+Uh+G7coNz
/H2CeE5n37BeucI55wql4CikrS3Cup5KudeuBi3dgrXyY+bIiZI+9WNsKZALaQ4WFUmfSj7W/RXe
AUhJkM3kgOb0AAAAAElFTkSuQmCC
)
C.2![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA8AAAASCAYAAACEnoQPAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAALtJREFU
OE/Nk9sVhCAMRENH9EMXFEET9EAB1ME59pAmsgmPFRF15Wv5UuQymUlUxAuGpZQat+bvAo+LT862
z+f+HMZIlq2IHfDpW+zU3NFzIm8jYUb4mS9o/DOMWMEimPwbuE80+bdl74oLnjvpGpyNJYFnz8Mg
YLQENUCgYEoLwOwtuJuwzjeEEDLkNJB2WynnEkaKdpZ2rqCoH2BRagPS9fjk2fBHUV/6MTanCbRb
g6UUUV9SbnH/Cn8A/r2EUaEPy7EAAAAASUVORK5CYII=
)
D.2
-
已知平面向量
、
的夹角为60°,则
=(
,1),|
|=1,则|
+2
|═( )
A.2
B.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA8AAAASCAYAAACEnoQPAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAALBJREFU
OE/Nk90NhSAMRmEj9mGLDsES7sAAncPEHViitnD9oTZReLpNfJD05Dut6InLqfLe6yP7XWBd3Gkd
P/v+G14XJ3vpnmXlXb1qFyTkxqsKIQBh+QQX4r4biwSA9ew9WakVBAKJHYcv5XGY5z+Uh+G7coNz
/H2CeE5n37BeucI55wql4CikrS3Cup5KudeuBi3dgrXyY+bIiZI+9WNsKZALaQ4WFUmfSj7W/RXe
AUhJkM3kgOb0AAAAAElFTkSuQmCC
)
C.2![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA8AAAASCAYAAACEnoQPAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAALtJREFU
OE/Nk9sVhCAMRENH9EMXFEET9EAB1ME59pAmsgmPFRF15Wv5UuQymUlUxAuGpZQat+bvAo+LT862
z+f+HMZIlq2IHfDpW+zU3NFzIm8jYUb4mS9o/DOMWMEimPwbuE80+bdl74oLnjvpGpyNJYFnz8Mg
YLQENUCgYEoLwOwtuJuwzjeEEDLkNJB2WynnEkaKdpZ2rqCoH2BRagPS9fjk2fBHUV/6MTanCbRb
g6UUUV9SbnH/Cn8A/r2EUaEPy7EAAAAASUVORK5CYII=
)
D.2