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1、word实验一练习1 使用who whos查看变量内容 a=2.5a = 2.5000 b=1 2;3 4b = 1 2 3 4 c=ac =a d=sin(a*b*pi/180)d = 0.0436 0.0872 0.1305 0.1736 e=a+ce = 99.5000 whoYour variables are:a b c d e whos Name Size Bytes Class Attributes a 1x1 8 double b 2x2 32 double c 1x1 2 char d 2x2 32 double e 1x1 8 double 2 绘制柱状图 x=1 2 3
2、4 5; y=sin(x)y = 0.8415 0.9093 0.1411 -0.7568 -0.9589 plot(y,DisplayName,y,YDataSource,y);figure(gcf) hist(y);figure(gcf); x=1 2 3 4 5; y=sin(x)y = 0.8415 0.9093 0.1411 -0.7568 -0.9589 hist(y);figure(gcf);自我练习x=1 3 5 7 9y=2*xplot(y)实验二 练习1使用全下标方式获取a矩阵中第二列子矩阵块a=1 2 3;4 5 6;7 8 9b=a(:,2)a = b = 1 2 3
3、2 4 5 6 5 7 8 98 2使用logspace函数创建0-4*pi行向量 有二十个元素,查看元素分布情况。 c=logspace(0,4*pi,20)c = 1.0e+12 *Columns 1 through 7 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Columns 8 through 14 0.0000 0.0000 0.0000 0.0000 0.0000 0.0001 0.0004 Columns 15 through 20 0.0018 0.0083 0.0382 0.1752 0.8035 3.68443 验证关
4、系式A=1/3 0 0;0 1/4 0;0 0 1/7B=inv(A)*inv(inv(A)-eye(3)*6*AZUO=A(B*A)YOU=6*A+B*AA = 0.3333 0 0 0 0.2500 0 0 0 0.1429B = 3.0000 0 0 0 2.0000 0 0 0 1.0000ZUO = 3.0000 0 0 0 2.0000 0 0 0 1.0000YOU = 3.0000 0 0 0 2.0000 0 0 0 1.00004 將矩正的乘除运算改为数组的点除运算A=1 2 3;4 5 6;7 8 9B=1 1 1;2 2 2;3 3 3A*Bc1=A.*Bd1=A/Bd
5、2=A./BA =B = 1 2 31 1 1 4 5 62 2 2 7 8 9 3 3 3ans = c1 = 14 14 141 2 3 32 32 328 10 12 50 50 5021 24 27Warning: Matrix is singular to working precision. In matlabP322 at 5 d1 = NaN NaN NaN NaN NaN NaN NaN NaN Nad2 = 1.0000 2.0000 3.0000 2.0000 2.5000 3.00002.3333 2.6667 3.00005 使用数组编辑窗口查看变量a，b，c6 使用
6、setfield命令进展上述修改 student(1)=struct(name,Rose,Id,20030102,score,95,93,84,72,88)student = name: Rose Id: 20030102 score: 95 93 84 72 88 student=setfield(student,1,score,95,73,84,72,88)student = name: Rose Id: 20030102 score: 95,73,84,72,887 使用图形和文字显示average的各元胞内容 student(1)=struct(name,John,Td,2003011
7、5,scores,85,96,74,82,68)student = name: John Td: 20030115 scores: 85 96 74 82 68 student(2)=struct(name,Rose,Td,20030102,scores,95,93,84,72,88)student = 1x2 struct array with fields: name Td scores student(3)=struct(name,Billy,Td,20030117,scores,72,83,78,80,83)student = 1x3 struct array with fields:
8、 name Td scores all_scores=cat(1,student.scores)all_scores = 85 96 74 82 68 95 93 84 72 88 72 83 78 80 83 average_scores=mean(all_scores)average_scores = 84.0000 90.6667 78.6667 78.0000 79.6667方法一 average=平均成绩,average_scoresaverage = 平均成绩 1x5 double方法二 average(1)=平均成绩average = 平均成绩 average(2)=averag
9、e_scoresaverage = 平均成绩 1x5 double方法三 average1=平均成绩; average2=average_scoresaverage = 平均成绩 1x5 double自我练习1 使用LU和QR分解线性方程A=2 -3 0 2;1 5 2 1;3 -1 1 -1;4 1 2 2B=8;2;7;12X=ABL,U=lu(A)X=U(LB)Q,R=qr(A)X=R(QB)A =B = 2 -3 0 2 8 1 5 2 1 2 3 -1 1 -1 7 4 1 2 2 12X =L = 3.00000.5000 -0.7368 1.0000 0 0.00000.2500 1.0000 0 0 -1.00000.7500 -0.3684 0.5000 1.0000 1.00001.0000 0 0 0U =X = 4.0000 1.0000 2.0000 2.0000 3.0000 0 4.7500 1.5000 0.5000 0.0000 0 0 0.1053 1.3684-1.0000 0 0 0 -3.0000 1.0000Q = -0.3651 0.5000 0.6708 0.4
