向量考试题及答案
一、单项选择题(每题2分,共20分)
1.若向量\(\vec{a}=(1,2)\),\(\vec{b}=(3,x)\),且\(\vec{a}\parallel\vec{b}\),则\(x\)的值为()
A.3B.4C.5D.6
2.向量\(\vec{a}=(2,-1)\)的模\(\vert\vec{a}\vert\)等于()
A.\(\sqrt{5}\)B.\(\sqrt{3}\)C.\(\sqrt{2}\)D.1
3.已知\(\vec{a}=(1,1)\),\(\vec{b}=(-1,1)\),则\(\vec{a}+\vec{b}\)等于()
A.\((0,2)\)B.\((2,0)\)C.\((1,1)\)D.\((-1,-1)\)
4.若向量\(\vec{a}\)与向量\(\vec{b}\)的夹角为\(90^{\circ}\),则()
A.\(\vec{a}\cdot\vec{b}=0\)B.\(\vec{a}\cdot\vec{b}=1\)C.\(\vec{a}\cdot\vec{b}=-1\)D.\(\vec{a}\cdot\vec{b}=\vert\vec{a}\vert\vert\vec{b}\vert\)
5.已知向量\(\vec{a}=(3,4)\),将其单位化后的向量为()
A.\((\frac{3}{5},\frac{4}{5})\)B.\((\frac{4}{5},\frac{3}{5})\)C.\((3,4)\)D.\((-3,-4)\)
6.若\(\vec{a}=(2,m)\),\(\vec{b}=(-1,2)\),且\(\vec{a}\perp\vec{b}\),则\(m\)的值为()
A.1B.-1C.2D.-2
7.向量\(\vec{a}=(1,-2)\),\(\vec{b}=(-2,4)\),则\(\vec{a}\)与\(\vec{b}\)()
A.平行且同向B.平行且反向C.不平行D.垂直
8.已知\(\vec{a}=(x,1)\),\(\vec{b}=(3,-2)\),若\(\vec{a}\parallel\vec{b}\),则\(x\)等于()
A.\(\frac{3}{2}\)B.\(-\frac{3}{2}\)C.\(\frac{2}{3}\)D.\(-\frac{2}{3}\)
9.向量\(\vec{a}=(4,-3)\)在向量\(\vec{b}=(2,1)\)上的投影为()
A.\(\frac{5}{\sqrt{5}}\)B.\(\frac{5}{\sqrt{10}}\)C.\(\frac{5}{\sqrt{13}}\)D.\(\frac{5}{\sqrt{17}}\)
10.若\(\vec{a}=(1,1)\),\(\vec{b}=(1,-1)\),则\(\vec{a}\cdot\vec{b}\)的值为()
A.0B.1C.2D.-1
二、多项选择题(每题2分,共20分)
1.以下关于向量的说法正确的是()
A.零向量的模为0B.单位向量的模为1
C.若\(\vec{a}\parallel\vec{b}\),则\(\vec{a}\)与\(\vec{b}\)的方向相同或相反
D.向量的加法满足交换律和结合律
2.已知向量\(\vec{a}=(1,2)\),\(\vec{b}=(-1,3)\),则()
A.\(\vec{a}+\vec{b}=(0,5)\)B.\(\vec{a}-\vec{b}=(2,-1)\)
C.\(\vec{a}\cdot\vec{b}=5\)D.\(\vert\vec{a}\vert=\sqrt{5}\)
3.下列向量中,与向量\(\vec{a}=(1,1)\)垂直的向量有()
A.\((-1,1)\)B.\((1,-1)\)C.\((-1,-1)\)D.\((2,-2)\)
4.向量的运算包括()
A.加法B.减法C.数乘D.数量积
5.若向量\(\vec{a}=(x_1,y_1)\),\(\vec{b}=(x_2,y_2)\),则下列正确的是()
A.\(\vec{a}\parallel\vec{b}\)的充要条件是\(x_1y_2-x_2y_1=0\)
B.\(