答案：
第1空:
否
答案：
第1空:
否
,|b|=2,且( )⊥a,则向量a和b的夹角是________度.A. 最多有n-1条
B. 至少有n-1条
C. 最多有n条
D. 至少有n条
, INCLUDEPICTURE ＼d "http://mooc1-2.chaoxing.com/ananas/latex/p/581268" ＼* MERGEFORMATINET 
,则 INCLUDEPICTURE ＼d "http://mooc1-2.chaoxing.com/ananas/latex/p/320327" ＼* MERGEFORMATINET 
( )A. 0
B. (1,-1)
C. INCLUDEPICTURE ＼d "https://mooc1-2.chaoxing.com/ananas/latex/p/113749" ＼* MERGEFORMATINET 
D. INCLUDEPICTURE ＼d "http://p.ananas.chaoxing.com/star3/origin/67a557abb156385a453c741fec934ab8" ＼* MERGEFORMATINET 
A. -4
B. 0
C. 2
D. 4
A. 顶点个数相等
B. 边数相等
C. 度数相同的顶点个数相相同
D. 两个图的形状相同
矩阵, INCLUDEPICTURE ＼d "http://mooc1-2.chaoxing.com/ananas/latex/p/23856" ＼* MERGEFORMATINET 
有解,则( )
A. INCLUDEPICTURE ＼d "https://p.ananas.chaoxing.com/star3/origin/79c9956d2c877d0df05eb529e6365644.png" ＼* MERGEFORMATINET 
B. INCLUDEPICTURE ＼d "https://p.ananas.chaoxing.com/star3/origin/ccd273e1009d4e370c43ab0c0caa5d2e.png" ＼* MERGEFORMATINET 
C. INCLUDEPICTURE ＼d "https://p.ananas.chaoxing.com/star3/origin/2931de922a6acc59de6d04e023beaa5d.png" ＼* MERGEFORMATINET 
D. INCLUDEPICTURE ＼d "https://p.ananas.chaoxing.com/star3/origin/84d415fa7a70ee3c0d1caba60c13ab66.png" ＼* MERGEFORMATINET 
A. INCLUDEPICTURE ＼d "https://p.ananas.chaoxing.com/star3/origin/cbfa63facc47534b5791c0edb3985858.png" ＼* MERGEFORMATINET 
B. INCLUDEPICTURE ＼d "https://p.ananas.chaoxing.com/star3/origin/f00401a0806543e0c700b626719028d3.png" ＼* MERGEFORMATINET 
C. INCLUDEPICTURE ＼d "https://p.ananas.chaoxing.com/star3/origin/b68a546fa6a2abd42fdf096156b763f0.png" ＼* MERGEFORMATINET 
D. INCLUDEPICTURE ＼d "https://p.ananas.chaoxing.com/star3/origin/d7b17fc70b316cb4a0d33d9111f5a0fe.png" ＼* MERGEFORMATINET 
A. 欧拉
B. 迪克斯特拉
C. 克鲁斯卡尔
D. 普里姆
A. 线性方程组AX=b无解
B. 线性方程组AX=b有无穷解
C. 线性方程组AX=b有唯一解
D. 齐次线性方程组AX=0只有零解
