matlab第2章作业.docx
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matlab第2章作业
电信系电气本0902班学号:
09401240217姓名:
孙振东
第2章MATLAB基本使用方法及常用功能介绍
2.1
>>(9*(10-1)+19)/2^2
ans=25
2.3
>>A=[1,1,1;1,2,3;1,3,6];
>>A(2,:
)
ans=123
2.5
>>A=eye(4)
A=1000
0100
0010
0001
2.7
>>v=[12345];
>>diag(v)
ans=10000
02000
00300
00040
00005
>>diag(v,-1)
ans=000000
100000
020000
003000
000400
000050
>>diag(v,1)
ans=010000
002000
000300
000040
000005
000000
2.9
>>2*pi
ans=6.2832
2.11
>>A=[1,2,3;4,5,6;7,8,9];
>>B=[1,2,3;4,5,6;7,8,9];
>>C=A*B
C=303642
668196
102126150
2.13
>>a=2:
8
a=2345678
2.15
>>A=[1,2,3;4,5,6;7,8,9];
>>B=A(1:
2,:
)
B=123
456
2.17
>>x1=5*cos(0.1*pi)/(1+sqrt
(2))
x1=1.9697
>>x2=5*sin(0.1*pi)/(1+sqrt
(2))
x2=0.6400
2.19
>>x1=[12345]
x1=12345
>>x2=[1,2,3,4,5]
x2=12345
>>x3=[1;2;3;4;5]'
x3=12345
2.21
>>A=[102030];
>>B=[405060];
>>C=dot(A,B)
C=3200
>>C=cross(A,B)
C=-300600-300
2.23
>>A=[1,3,5;2,4,6;3,5,7];
>>B=[2,4,6;1,3,5;3,5,7];
>>C=A.*B
C=21230
21230
92549
2.25
>>A=[1,3,5;2,4,6;3,5,7];
>>C=A.^2
C=1925
41636
92549
2.27
>>A=ones(3,4);
>>C={A,[1,2];'cell',[1;2]}
C=[3x4double][1x2double]
'cell'[2x1double]
2.29
>>z=5+5i;
>>Am=abs(z)
Am=7.0711
>>Fm=angle(z)
Fm=0.7854
2.31
>>A=[120;2,5-1;410-1];
>>B=inv(A)
B=52-2
-2-11
0-21
2.33
>>A=[120;25-1;410-1];
>>d=eig(A)
d=3.7321
0.2679
1.0000
>>[B,C]=eig(A)
B=-0.2440-0.91070.4472
-0.33330.33330.0000
-0.9107-0.24400.8944
C=3.732100
00.26790
001.0000
2.35
>>P=[250414];
>>poly2sym(P)
ans=2*x^5+5*x^4+4*x^2+x+4
2.37
>>P=[12.5020.52];
>>r=roots(P)
r=-2.7709
0.5611+0.7840i
0.5611-0.7840i
-0.4257+0.7716i
-0.4257-0.7716i
>>poly(r)
ans=1.00002.50000.00002.00000.50002.0000
2.39
>>p=[1234];
>>q=[102030];
>>c=conv(p,q)
c=1040100160170120
>>[s,r]=deconv(c,p)
s=102030
r=000000
2.41
>>x=0:
0.1:
1;
>>y=[-.4471.9783.286.167.087.347.669.569.489.3011.2];
>>p=polyfit(x,y,2)
p=-9.810820.1293-0.0317
2.43
>>y=sym('2*sin(x)*cos(x)')
y=2*cos(x)*sin(x)
>>y=simple(y)
y=sin(2*x)
2.45
>>symsx
>>f1=x^3+x^2+4*x+4;
>>f2=x^2+4*x+10;
>>f=f1+f2
f=x^3+2*x^2+8*x+14
>>y=sqrt(x^5)
y=(x^5)^(1/2)
>>z=log10(x)
z=log(x)/log(10)
2.47
>>symsabcdetnxyz;
>>y=a*x^n+b*t+c;
>>y1=subs(y,[abc],[sin(t)log(z)d*exp(2*t)])
y1=x^n*sin(t)+t*log(z)+d*exp(2*t)
>>y2=subs(y,[nc],[3pi])
y2=a*x^3+pi+b*t
>>y3=subs(y,c,1:
2:
5)
y3=[a*x^n+b*t+1,a*x^n+b*t+3,a*x^n+b*t+5]
>>y4=subs(y,c,[12;34])
y4=[a*x^n+b*t+1,a*x^n+b*t+2]
[a*x^n+b*t+3,a*x^n+b*t+4]
2.49
>>symsx;
>>y=x^4-5*x^3+5*x^2+5*x-6;
>>y1=factor(y)
y1=(x-1)*(x-2)*(x-3)*(x+1)
2.51
>>symsx;
>>y=2*cos(x)^2-sin(x)^2;
>>y1=simplify(y)
y1=3*cos(x)^2–1
2.53
>>f=sym
(1);
>>F=laplace(f)
F=1/s
2.55
>>symst;
>>f=2+sin(3*t)+exp(-2*t);
>>F=laplace(f)
F=1/(s+2)+3/(s^2+9)+2/s
>>[n,d]=numden(F)
n=3*s^3+7*s^2+33*s+36
d=s^4+2*s^3+9*s^2+18*s
2.57
>>symsts;
>>fs11=2/(s+1)-1/(s+2);
>>fs12=1/(s+1)-1/(s+2);
>>fs21=-2/(s+1)+2/(s+2);
>>fs22=-1/(s+1)+2/(s+2);
>>Fs=[fs11,fs12;fs21,fs22];
>>Mt=ilaplace(Fs)
Mt=[2/exp(t)-1/exp(2*t),1/exp(t)-1/exp(2*t)]
[2/exp(2*t)-2/exp(t),2/exp(2*t)-1/exp(t)]
2.59
>>symsTnza;
>>F1=ztrans(n*T)
F1=(T*z)/(z-1)^2
>>F2=ztrans((n*T)^2)
F2=(T^2*(z^2+z))/(z-1)^3
>>F31=ztrans(exp(a*n*T))
F31=z/(z-exp(T*a))
>>F32=simple(ztrans(exp(a*n*T)))
F32=z/(z-exp(T*a))
2.61
>>x=0:
0.1*pi:
pi;
y=sin(x).*cos(x);
plot(x,y)
2.63
>>x=(0:
pi/50:
2*pi)';
>>k=0.4:
0.1:
1;
>>Y=cos(x)*k;
>>plot(Y)
2.65
>>x=0:
0.5:
4*pi;
>>y1=exp(-0.1*x).*sin(x);
>>y2=exp(-0.1*x).*sin(x+1);
>>plot(x,y1,'+g');
>>holdon
>>plot(x,y2,':
r');
>>holdoff
2.67
>>x=pi*(0:
1000)/1000;
>>y1=sin(x);
>>y2=sin(10*x);
>>y12=sin(x).*sin(10*x);
>>subplot(2,2,1),plot(x,y1),axis([0,pi,-1,1])
>>subplot(2,2,2),plot(x,y2),axis([0,pi,-1,1])
>>subplot('position',[0.2,0.05,0.6,0.45])
>>plot(x,y12),axis([0,pi,-1,1])
2.69
>>x=0:
0.5:
4*pi;
>>y1=exp(-0.1*x).*sin(x);
>>y2=exp(-0.1*x).*sin(x+1);
>>plot(x,y1,x,y2,':
')
>>legend('第一条','第二条')
2.71
>>theta=0:
0.1:
2*pi;
>>polar(theta,sin(2*theta).*cos(2*theta),'--r')
2.73
>>t=0:
pi/50:
10*pi;
>>plot3(sin(t),cos(t),t)
>>gridon
2.75
>>[X,Y]=meshgrid(-8:
0.5:
8);
>>R=sqrt(X.^2+Y.^2)+eps;
>>Z=sin(R)./R;
>>mesh(X,Y,Z)
2.77
>>figure
2.79
2.81
>>sum=0;
>>fork=1:
100
sum=sum+k;end
>>sum
sum=5050
2.83
>>sum=0;
>>k=1;
>>whilek<=100
sum=sum+k;
k=k+1;
end
>>sum
sum=5050
2.85
a=[123;456;789];
m=2;n=3;
ifm==n
a(m,n)=0;
elseifabs(m-n)==2
a((m-1),(n-1))=-1;
else
a(m,n)=-5;
end
a
a=
123
45-5
789
2.87
A=magic(3)
B=ones(4,3)
try
C=A*B;
catch
C=NaN
end
lasterr
>>e2_87
A=816
357
492
B=111
111
111
111
C=NaN
ans=
Errorusing==>mtimes
Innermatrixdimensionsmustagree.