matlab实验报告二

1、 Matlab实验报告实验2 数值数组及运算一、 实验目的（1） 掌握一维数组、二维数组、多项式和高维数组的创建（2） 掌握对数组操作的常用函数二、 实验内容使用冒号运算符创建下面各表达式对应的向量。>> x=logspace(1,3,3); x=10.1:3x = 10 100 1000>> x=logspace(1,3,5)x = 1.0e+003 * 0.0100 0.0316 0.1000 0.3162 1.0000利用MATLAB内置函数计算下面的值>> cosh(5)ans = 74.2099>> sinh(-2)ans = -3.6

2、269>> (exp(5)+exp(-5)/2ans = 74.2099>> help erf ERF Error function. Y = ERF(X) is the error function for each element of X. X must be real. The error function is defined as: erf(x) = 2/sqrt(pi) * integral from 0 to x of exp(-t2) dt. Class support for input X: float: double, single See al

3、so erfc, erfcx, erfinv. Overloaded functions or methods (ones with the same name in other directories) help sym/erf.m Reference page in Help browser doc erf>> erf(1.2)ans = 0.9103利用linspace函数创建下面表达式的对应向量>> x=0:10; x=linspace(0,10,11)x = 0 1 2 3 4 5 6 7 8 9 10>> x=0:0.2:10; x=linspa

4、ce(0,10,51)x = Columns 1 through 16 0 0.2000 0.4000 0.6000 0.8000 1.0000 1.2000 1.4000 1.6000 1.8000 2.0000 2.2000 2.4000 2.6000 2.8000 3.0000 Columns 17 through 32 3.2000 3.4000 3.6000 3.8000 4.0000 4.2000 4.4000 4.6000 4.8000 5.0000 5.2000 5.4000 5.6000 5.8000 6.0000 6.2000 Columns 33 through 48 6

5、.4000 6.6000 6.8000 7.0000 7.2000 7.4000 7.6000 7.8000 8.0000 8.2000 8.4000 8.6000 8.8000 9.0000 9.2000 9.4000 Columns 49 through 51 9.6000 9.8000 10.0000>> x=-12:12; x=linspace(-12,12,25)x = -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12>> x=10:-1:1; x=linspace(10,1

6、,10)x = 10 9 8 7 6 5 4 3 2 1>> x=10 9 8 7x = 10 9 8 7>> x=10 9 8 7;y=1 2 3 4' z=x-y'>> zz = 9 7 5 3计算>> A=1 2 3 3;2 3 5 7;1 3 5 7;3 2 3 9;1 8 9 4;>> B=1+4i 4 3 6 7;2 3 3 5 5;2 6+7i 5 3 4;1 8 9 4 3;>> C=A*B;>> CC = 1.0e+002 * 0.1400 + 0.0400i 0.5200 +

7、 0.2100i 0.5100 0.3700 0.3800 0.2500 + 0.0800i 1.0300 + 0.3500i 1.0300 0.7000 0.7000 0.2400 + 0.0400i 0.9900 + 0.3500i 1.0000 0.6400 0.6300 0.2200 + 0.1200i 1.0800 + 0.2100i 1.1100 0.7300 0.7000 0.3900 + 0.0400i 1.1400 + 0.6300i 1.0800 0.8900 0.9500 >> D=C(4:5,3:5);>> DD = 111 73 70 108

8、89 95>> A=1 2 3 3;2 3 5 7;1 3 5 7;3 2 3 9;1 8 9 4;>> A=1 2 3 3;2 3 5 7;1 3 5 7;3 2 3 9;1 8 9 4A = 1 2 3 3 2 3 5 7 1 3 5 7 3 2 3 9 1 8 9 4>> A=4 12 20;12 45 78;20 78 136;>> B=1 2 3;4 5 6;7 8 0;>> I=1 0 0;0 1 0;0 0 1;>> A+5*Bans = 9 22 35 32 70 108 55 118 136>>

9、; A-B+Ians = 4 10 17 8 41 72 13 70 137>> A.*Bans = 4 24 60 48 225 468 140 624 0>> A*Bans = 192 228 84 738 873 306 1284 1518 528>> A.Bans = 1.0e+015 * 0.0000 0.0000 0.0000 0.0000 0.0000 0.0002 0.0000 1.3701 0.0000>> ABWarning: Matrix is close to singular or badly scaled. Resul

10、ts may be inaccurate. RCOND = 1.328379e-018.ans = 1.0e+015 * 0.0000 -0.0000 3.6192 -0.0000 0.0000 -7.2384 0.0000 -0.0000 3.6192>> A/Bans = 9.3333 -1.3333 0.0000 40.0000 -7.0000 0.0000 70.6667 -12.6667 0.0000>> A(find(A>50)&(A<100)ans = 78 78>> B(find(B>5)ans = 7 8 6>

11、;> A=1 2 NaN Inf -Inf 5 NaNA = 1 2 NaN Inf -Inf 5 NaN>> isnan(A)ans = 0 0 1 0 0 0 1>> isfinite(A)ans = 1 1 0 0 0 1 0>> isinf(A)ans = 0 0 0 1 1 0 0>> any(A)ans = 1>> all(A)ans = 1求出以下矩阵的逆矩阵>> A=1 -5 -2;3 4 -9;-7 2 6A = 1 -5 -2 3 4 -9 -7 2 6>> B=sin(1) sin(

12、-5) sin(-2);sin(3) sin(4) sin(9); sin(-7) sin(2) sin(6)B = 0.8415 0.9589 -0.9093 0.1411 -0.7568 0.4121 -0.6570 0.9093 -0.2794>> inv(A)ans = -0.1673 -0.1036 -0.2112 -0.1793 0.0319 -0.0120 -0.1355 -0.1315 -0.0757>> inv(B)ans = 6.8645 23.4969 12.3171 9.7255 35.0011 19.9746 15.5090 58.6555 3

13、2.4631>> A=1 2 3;4 5 6;7 8 9;>> B=flipud(A)B = 7 8 9 4 5 6 1 2 3>> u=1 2 3;>> v=4 5 6;>> A=u;vA = 1 2 3 4 5 6用两行语句实现从C中引用列向量>> C=11 5;5 1;18 7;>> s=C(:,1)s = 11 5 18>> t=C(:,2)t = 5 1 7使用diag函数和冒号运算符创建下面矩阵>> diag(1:1:4)ans = 1 0 0 0 0 2 0 0 0 0 3

14、 0 0 0 0 4>> diag(4:-1:1)ans = 4 0 0 0 0 3 0 0 0 0 2 0 0 0 0 1>> diag(1:6:19)ans = 1 0 0 0 0 7 0 0 0 0 13 0 0 0 0 19使用diag函数创建nxn对称三对角阵>> a=2 2 2 2;>> b=-1 -1 -1;>> D=diag(a)+diag(b,-1)+diag(b,1)D = 2 -1 0 0 -1 2 -1 0 0 -1 2 -1 0 0 -1 2创建矩阵>> e=eye(3);>> E=f

15、liplr(e)E = 0 0 1 0 1 0 1 0 0>> a=2*eye(5)-ones(5)a = 1 -1 -1 -1 -1 -1 1 -1 -1 -1 -1 -1 1 -1 -1 -1 -1 -1 1 -1 -1 -1 -1 -1 1>> b=tril(a)b = 1 0 0 0 0 -1 1 0 0 0 -1 -1 1 0 0 -1 -1 -1 1 0 -1 -1 -1 -1 1>> b(:,5)=1b = 1 0 0 0 1 -1 1 0 0 1 -1 -1 1 0 1 -1 -1 -1 1 1 -1 -1 -1 -1 1使用rehape函数

16、和冒号运算符创建矩阵>> reshape(2:2:24,3,4)ans = 2 8 14 20 4 10 16 22 6 12 18 24>> reshape(-5:1:6,2,6)ans = -5 -3 -1 1 3 5 -4 -2 0 2 4 6（a）找出每个矩阵各列中绝对值最大的元素（b）找出每个矩阵各行中绝对值最大的元素>> c=C(:,1)c = 11 2 1>> max(real(c)ans = 11>> d=C(:,2)d = -4 2 11>> max(real(d)ans = 11>> e=C

17、(1,:)e = 11 -4>> max(real(e)ans = 11>> f=C(2,:)f = 2 2>> max(real(f)ans = 2>> c=D(:,1)c = 13 2 13>> max(real(c)ans = 13>> d=D(:,2)d = -6 2 23>> >> max(real(d)ans = 23>> e=D(1,:)e = 13 -6>> max(real(e)ans = 13>> f=D(2,:)f = 2 2>>

18、 max(real(f)ans = 2>> c=E(:,1)c = 4.5000 -3.0000 -0.7500>> max(real(c)ans = 4.5000>> d=E(:,2)d = 1.0000 1.0000 1.7500>> max(real(d)ans = 1.7500>> e=E(1,:)e = 4.5000 1.0000>> max(real(e)ans = 4.5000>> f=E(2,:)f = -3 1>> max(real(f)ans = 1思考下面的程序>>

19、 A=ones(3,2);>> B=2*ones(2,3);>> A*B;>> A(2,3)=2;>> A*B;? Error using => mtimesInner matrix dimensions must agree.>> A*B? Error using => mtimesInner matrix dimensions must agree.>> u=0:3;>> v=(3:-1:0)'>> w=u.*v;? Error using => timesMatrix dimensions must agree.>> clear all>> A=ones(3,3);>&g