Matlab实验内容.docx
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Matlab实验内容
Matlab实验内容
第1章
1.用help命令可以查询到自己的工作目录。
输入help命令:
help<函数名>
2.MATLAB的主要优点:
通过例1-1至例1-4的验证,MATLAB的优点是MATLAB以矩阵作为数据操作的基本单位,使得矩阵运算变得非常简捷,方便,高效。
还提供了丰富的数值计算函数。
MATLAB绘图十分方便,只需输入绘图命令,MATLAB便可自动绘出图形。
3.INV(X)istheinverseofthesquarematrixX。
AwarningmessageisprintedifXisbadlyscaledornearlysingular.PLOT(X,Y)plotsvectorYversusvectorX.IfXorYisamatrix,thenthevectorisplottedversustherowsorcolumnsofthematrix,whicheverlineup.IfXisascalarandYisavector,length(Y)disconnectedpointsareplotted.PLOT(Y)plotsthecolumnsofYversustheirindex.IfYiscomplex,PLOT(Y)isequivalenttoPLOT(real(Y),imag(Y)).InallotherusesofPLOT,theimaginarypartisignored.Forvectors,MAX(X)isthelargestelementinX.Formatrices,
MAX(X)isarowvectorcontainingthemaximumelementfromeachcolumn.ForN-Darrays,MAX(X)operatesalongthefirstnon-singletondimension.[Y,I]=MAX(X)returnstheindicesofthemaximumvaluesinvectorI.Ifthevaluesalongthefirstnon-singletondimensioncontainmorethanonemaximalelement,theindexofthefirstoneisreturned.ROUND(X)roundstheelementsofXtothenearestintegers.MAX(X,Y)returnsanarraythesamesizeasXandYwiththelargestelementstakenfromXorY.Eitheronecanbeascalar。
[Y,I]=MAX(X,[],DIM)operatesalongthedimensionDIM.Whencomplex,themagnitudeMAX(ABS(X))isused,andtheangleANGLE(X)isignored.NaN'sareignoredwhencomputingthemaximum.
4.sinx是以步长为∏/10,起始值为0,终止值为2∏的正弦函数。
5.MATLAB是一种用于数值计算、可视化及编程的高级语言和交互式环境。
使用MATLAB,可以分析数据,开发算法,创建模型和应用程序。
借助其语言、工具和内置数学函数,您可以探求多种方法,比电子表格或传统编程语言(如C/C++或Java™)更快地求取结果。
第2章
1.
(1)w=sqrt
(2)*(1+0.34245*10^(-6))
w=1.4142
(2)a=3.5;
b=5;
c=-9.8;
x=(2*pi*a+(b+c)/(pi+a*b*c)-exp
(2))/(tan(b+c)+a)
x=0.9829
(3)a=3.32;
b=-7.9;
y=2*pi*a^2*((1-pi/4)*b-(0.8333-pi/4)*a)
y=-128.4271
(4)t=[2,1-3i;5,-0.65];
z=0.5*exp(2*t)*log(t+sqrt(1+t*t))
z=
1.0e+004*
0.0048+0.0002i0.0048-0.0034i
1.58992.0090-1.3580i
2.
(1)A+6B=[47,23,-10;12,37,26;-15,73,7;]
A^2-B+I=[18,-216,18;23,533,110;22,868,526]
(2)A*B=[14,14,16;-10,51,21;125,328,180]
A.*B=[-8,15,4;0,35,24;-9,122,0]
B*A=[-11,0,-15;7,228,533,-1,28]
(3)A/B=[1.2234,-0.925,2.9787;-0.9468,2.3511,-0.9574;4.6170,3.8723,13.8936]
B\A=[-0.5106,-8.6170,-1.1277;0.7340,17.5745,1.8085;-0.8830,-21.2128,0.4043]
(4)[A,B]=[-1,5,-4,8,3,-1;0,7,8,2,5,3;3,61,7,-3,2,0]
[A([1,3],:
);B^2]=[-1,5,4;3,6,7;73,37,1;17,7,3;-20,1,9]
3.
(1)A=[2310-0.7780;41-45655;325032;6-9.54543.14]
A=
23.000010.0000-0.77800
41.0000-45.000065.00005.0000
32.00005.0000032.0000
6.0000-9.540054.00003.1400
B=A(1:
3,:
)
B=
23.000010.0000-0.77800
41.0000-45.000065.00005.0000
32.00005.0000032.0000
C=A(:
1:
2)
C=
23.000010.0000
41.0000-45.0000
32.00005.0000
6.0000-9.5400
D=A(2:
4,3:
4)
D=
65.00005.0000
032.0000
54.00003.1400
E=B*C
E=
1.0e+003*
0.9141-0.2239
1.20802.7123
1.1330-0.2103
(2)Eans=
01
00
01
E&D
ans=
11
01
11
E|D
ans=
11
11
11
~D
ans=
00
10
00
~E
ans=
00
00
00
4.H=hilb(5);
P=pascal(5);
Hh=det(H)
Hh=3.7493e-012
Hp=det(P)
Hp=1
Th=cond(H)
Th=4.7661e+005
Tp=cond(P)
Tp=8.5175e+003
条件数越趋近于1,矩阵的性能越好,所以帕斯卡矩阵性能更好。
5.A=[-29,6,18;20,5,12;-8,8,5]
A=
-29618
20512
-885
[V,D]=eig(A)
V=
0.71300.28030.2733
-0.6084-0.78670.8725
0.34870.55010.4050
D=
-25.316900
0-10.51820
0016.8351
V为A的特征向量,D为A的特征值。
它们之间满足A*V=V*D
第3章
1.
n=input(‘请输入一个三位数:
’);
a=fix(n/100);
b=fix((n-a*100)/10);
c=n-a*100-b*10;
d=c*100+b*10+a
2.
(1)
n=input('请输入成绩');
switchn
casenum2cell(90:
100)
p='A';
casenum2cell(80:
89)
p='B';
casenum2cell(70:
79)
p='C';
casenum2cell(60:
69)
p='D';
otherwise
p='E';
end
price=p
(2)n=input('请输入成绩');
ifn>=90&n<=100
p='A';
elseifn>=80&n<=89
p='B';
elseifn>=70&n<=79
p='C';
elseifn>=60&n<=69
p='D';
else
p='E';
end
price=p
(3)try
n;
catch
price='error'
end
3.
(1)方法一:
n=[1,5,56,4,3,476,45,6,3,76,45,6,4,3,6,4,23,76,908,6];
a=n
(1);
b=n
(1);
form=2:
20
ifn(m)>a
a=n(m);
elseifn(m)
b=n(m);
end
end
max=a
min=b
(2)方法二:
n=[1,5,56,4,3,476,45,6,3,76,45,6,4,3,6,4,23,76,908,6];
min=min(n)
max=max(n)
4.
b=[-3.0:
0.1:
3.0];
forn=1:
61
a=b(n);
y(n)=(exp(0.3*a)-exp(-0.3*a))/2*sin(a+0.3)+log((0.3+a)/2);
end
y
5.
y1=0;
y2=1;
n=input('请输入n的值:
');
fori=1:
n
y1=y1+1/i^2;
y2=y2*((4*i*i)/((2*i-1)*(2*i+1)));
end
y1
y2
6.
A=[1,1,1,1,1,1;2,2,2,2,2,2;3,3,3,3,3,3;4,4,4,4,4,4;5,5,5,5,5,5;6,6,6,6,6,6];
n=input('请输入n的值:
');
ifn<=5&n>=0
disp(A([n],:
));
elseifn<0
disp(lasterr);
elsedisp(A([6],:
));
disp(lasterr);
end
7.
(1)
f=[];
forn=1:
40
f(n)=n+10*log(n^2+5);
end
y=f(40)/(f(30)+f(20))
(2)
f=[];a=0;
forn=1:
40
f(n)=a+n*(n+1);
a=f(n);
end
y=f(40)/(f(30)+f(20))
8.
y=0;
m=input('输入m的值:
');
n=input('输入n值:
');
fori=1:
n
y=y+i^m;
end
y
****************************************************
functions=shi8_1(n,m)
s=0;
fori=1:
n
s=s+i^m;
end
****************************************************
shi8_1(100,1)+shi8_1(50,2)+shi8_1(10,1/2)
第4章
1.
(1)
x=-10:
0.05:
10;
y=x-x.^3./6;
plot(x,y)
(2)
x=-10:
0.5:
10;
ezplot('x^2+2*y^2-64',[-8,8]);
gridon;
2.
t=-pi:
pi/10:
pi;
y=1./(1+exp(-t));
subplot(2,2,1);bar(t,y);
title('条形图(t,y)');
axis([-pi,pi,0,1]);
subplot(2,2,2);
stairs(t,y,'b');
title('阶梯图(t,y)');
axis([-pi,pi,0,1]);
subplot(2,2,3);
stem(t,y,'k');
title('杆图(t,y)');
axis([-pi,pi,0,1]);
subplot(2,2,4);
loglog(t,y,'y');
title('对数坐标图(t,y)');
3.
(1)
t=0:
pi/50:
2*pi;
r=5.*cos(t)+4;
polar(t,r);
title('\rho=5*cos\theta+4');
(2)
t=-pi/3:
pi/50:
pi/3;
r=5.*((sin(t)).^2)./cos(t);
polar(t,r);
4.
(1)
t=0:
pi/50:
2*pi;
x=exp(-t./20).*cos(t);
y=exp(-t./20).*sin(t);
z=t;
plot3(x,y,z);
gridon;
(2)
[x,y]=meshgrid(-5:
5);
z=zeros(11)+5;
mesh(x,y,z);
shadinginterp;
5
[x,y,z]=sphere(20);
surf(x,y,z);
axisoff;
shadinginterp;
m=moviein(20);
fori=1:
20
axis([-i,i,-i,i,-i,i])
m(:
i)=getframe;
end
movie(m,4);
第5章
1.
A=randn(10,5)
x=mean(A)
y=std(A)
Max=max(max(A))
Min=min(min(A))
Sumhang=sum(A,2)
SumA=sum(Sumhang)
B=sort(A);
C=sort(B,2,'descend');
C
2.
(1)
a=0:
15:
90;
b=a./180.*pi;
s=sin(b)
c=0:
15:
75;
d=c./180.*pi;
t=tan(d)
e=input('请输入想计算的值:
');
S=sin(e/180*pi)
T=tan(e/180*pi)
S1=interp1(a,s,e,'spline')
T1=interp1(c,t,e,'spline')
P1=polyfit(a,s,5);
P2=polyfit(c,t,5);
S2=polyval(P1,e)
T2=polyval(P2,e)
(2)
n=[1,9,16,25,36,49,64,81,100];
N=sqrt(n);
x=input('jisuanzhi:
');
interp1(n,N,x,'cubic')
3.
N=64;
T=5;
t=linspace(0,T,N);
h=exp(-t);
dt=t
(2)-t
(1);
f=1/dt;
X=fft(t);
F=X(1:
N/2+1);
f=f*(0:
N/2)/N;
plot(f,abs(F),'-*')
4.
P=[2,-3,0,5,13];
Q=[1,5,8];
p=polyder(P)
q=polyder(P,Q)
[a,b]=polyder(P,Q)
5.
P1=[1,2,4,0,5];
P2=[0,1,2];
P3=[1,2,3];
P=P1+conv(P2,P3)
X=roots(P)
A=[-1,1.2,-1.4;0.75,2,3.5;0,5,2.5];
p=polyval(P,A)
第6章
1.
(1)
A=[1/2,1/3,1/4;1/3,1/4,1/5;1/4,1/5,1/6];
B=[0.95,0.67,0.52]';
X=A\B
X=
1.2000
0.6000
0.6000
(2)
C=[0.95,0.67,0.53]';
X=A\C
X=
3.0000
-6.6000
6.6000
b3变大后,X1,X3明显增大,X2符号改变了,且绝对值仍然等于X3的绝对值。
(3)
cond(A)
ans=
1.3533e+003
2.
(1)(M文件)
functionfx=funx(x)
fx=x^41+x^3+1;
x=fzero('funx',-1)
x=
-0.9525
(2)(M文件)
functionfx=funx2(x)
fx=x-sin(x)/x;
x2=fzero('funx2',0.5)
x2=
0.8767
(3)functionq=fun3(p)
x=p
(1);
y=p
(2);
z=p(3);
q
(1)=sin(x)+y^2+log(z)-7;
q
(2)=3*x+2^y-z^3+1;
q(3)=x+y+z-5;
options=optimset('Display','off');
x=fsolve(@fun3,[1,1,1]',options)
x=
0.5991
2.3959
2.0050
q=fun3(x)
q=
1.0e-010*
0.22130.38040.0009
3.
(1)functionyp=fun4(t,y)
yp=-(1.2+sin(10*t))*y;
t0=0;
tf=5;
y0=1;
[t,y]=ode23(@fun4,[t0,tf],y0);
tf=5;
y0=1;
[t,y]=ode23(@fun4,[t0,tf],y0);
t'
ans=
Columns1through9
00.06670.13750.20030.26950.35280.43620.50330.5663
Columns10through18
0.63690.69130.74570.80810.87380.95911.02771.09631.1600
Columns19through27
1.22461.30821.37141.43471.50011.58421.65301.72191.7858
Columns28through36
1.85011.93191.99532.05872.12362.20532.27452.34382.4080
Columns37through45
2.47192.55012.61402.67792.74192.81932.90462.96853.0323
Columns46through54
3.09593.17213.23643.30073.36423.43953.53283.59653.6602
Columns55through63
3.72383.79983.86423.92863.99204.06714.14084.21444.2800
Columns64through72
4.34324.41594.48124.54654.60944.68124.75674.83224.8990
Columns73through74
4.96205.0000
y'
ans=
Columns1through9
1.00000.90350.78220.68230.59840.54020.51820.51060.4976
Columns10through18
0.46560.42800.38440.33550.29360.25950.24690.24210.2382
Columns19through27
0.22900.20540.18190.15850.13870.12250.11640.11400.1122
Columns28through36
0.10800.09740.08640.07530.06580.05810.05490.05370.0529
Columns37through45
0.05110.04660.04150.03610.03160.02780.02580.02530.0249
Columns46through54
0.02410.02210.01970.01720.01500.01320.01220.01190.0117
Columns55through63
0.01140.01040.00930.00810.00710.00620.00580.00560.0055
Columns64through72
0.00540.00500.00450.00390.00340.00300.00270.00260.0026
Columns73through74
0.00250.0025
(2)
functionyp=funb(t,y)
yp=cos(t)-y/(1+t^2);
t0=0;
tf=5;
y0=1;[t,y]=ode23('funb',[t0,tf],y0);
t'
ans=
Columns1through9
00.50000.80161.10331.40771.75372.23012.52152.8129
Columns10through18
2.97273.13263.30013.50913.75494.03754.36374.75845.0000
y'
ans=
Columns1through9
1.00001.01461.03631.04501.01620.91570.64510.41220.1437
Columns10through18
-0.0122-0.1699-0.3330-0.5273-0.7327-0.9233-1.0649-1.1040-1.0534
4.
functionfx=mymin(x)