2013MATLAB(电子)平时测试答案.doc

1A=1,2,3,4,5,6,7,7.8;9,9,9,9,0,0,0,-2;4,4,4,4,4,7,7,89;8,8,7,54,3,8,0,12;9,9,9,9,0,0,0,-2;8,8,7,54,3,8,0,121)B=A(2:5,1:2:5)B = 9 9 0 4 4 4 8 7 3 9 9 02)C=AC(3,:)=3)D=AD(find(D=0)=0.1D = 1 2 3 4 5 6 7 7.8 9 9 9 9 0.1 0.1 0.1 -2 4 4 4 4 4 7 7 89 8 8 7 54 3 8 0.1 12 9 9 9 9 0.1 0.1 0.1 -2 8 8 7 54 3 8 0.1 124) E=max(A)E = 9 9 9 54 5 8 7 895) F=sort(A,1,descend) 9 9 9 54 5 8 7 89 9 9 9 54 4 8 7 12 8 8 7 9 3 7 0 12 8 8 7 9 3 6 0 7.8 4 4 4 4 0 0 0 -2 1 2 3 4 0 0 0 -22A=15,6,7,7.8;0,0,0,-2;44,7,7,89;3,8,0,12 1) B=rand(size(A)B = 0.95013 0.8913 0.82141 0.92181 0.23114 0.7621 0.4447 0.73821 0.60684 0.45647 0.61543 0.17627 0.48598 0.018504 0.79194 0.405712) C=A.*BC = 14.252 5.3478 5.7499 7.1901 0 0 0 -1.4764 26.701 3.1953 4.308 15.688 1.4579 0.14803 0 4.86853) D=A(find(A0&A10)D = 3 6 7 8 7 7 7.84) E=min(A,2)E = 6 -2 7 05) F=mean(A)F = 15.5 5.25 3.5 26.73x=-7.6;y=8.2;y=tan(abs(x)+abs(y)/abs(x+y)*exp(cos(x)y = 3.31274x=sqrt(1+pi);y=(exp(x)+log(sin(x)2-sin(x2)/(x-5*i)y = 0.56903 + 1.398i5 a=4 2 3;1 1 0;-1 2 3; c=a-5;b=a*inv(c)b = 0.57143 -0.71429 -0.28571 -0.42857 0.28571 -0.28571 -0.42857 -0.71429 0.714296A=1,-1,-1;2,-1,-3;3,2,-5;B=2;1;0;X=inv(A)*BX = 5 -4.4409e-016 37f=sym(sqrt(5*x-4)-sqrt(x)/(x-1);limit(f,sym(x),1)ans =28syms x yy=sqrt(x*sin(x)*sqrt(1-exp(x)diff(y)y =(x*sin(x)*(1-exp(x)(1/2)(1/2)ans =1/2/(x*sin(x)*(1-exp(x)(1/2)(1/2)*(sin(x)*(1-exp(x)(1/2)+x*cos(x)*(1-exp(x)(1/2)-1/2*x*sin(x)/(1-exp(x)(1/2)*exp(x)9f=sym(1/(arcsin(x)2)*sqrt(1-x*x);f1=int(f)f1 =-1/asin(x)10syms x y z x,y,z=solve(x*x-y*y+z,x+y-z,3*x-y-z-2)x =1/2y =-1/2z =011function fx=fun(x)fx=x*x+2*x-exp(x)+5;z=fzero(fun,200)z = 2.992912x=input(输入一个x的值：);if x=90y=成绩等级为Aelseif x=80y=成绩等级为Belseif x=70y=成绩等级为Celseif x=60y=成绩等级为Delse x60y=成绩等级为Eend请输入成绩:79x = 79y =成绩等级为C14x=-3:0.1:3;y=x-(x.3)/6;plot(x,y,r);title(x from -3 to 3);xlabel(Variable X);ylabel(Variable Y);text(2,1,曲线y=x-x3/3!);15x=linspace(1,10,101); y=log(x); f=polyfit(x,y,5); yy=polyval(f,x); plot(x,y,m,x,yy,y)16N=128; T=1; t=linspace(0,T,N); x=3*cos(20*t+pi/3).*exp(-5*t);dt=t(2)-t(1);f=1/dt;X=fft(x);F=X(1:N/2+1);f=f*(0:N/2)/N;plot(f,abs(F),-*);xlabel(Frequency);ylabel(|F(k)|);17syms L R C;Uc=dsolve(L*C*D2Uc+R*C*DUc+Uc=0,Uc(0)=1,DUc(0)=0)I=C*diff(Uc)Uc =1/2*(R*C+(R2*C2-4*L*C)(1/2)/(R2*C2-4*L*C)(1/2)*exp(-1/2*(R*C-(R2*C2-4*L*C)(1/2)/L/C*t)-1/2*(R*C-(R2*C2-4*L*C)(1/2)/(R2*C2-4*L*C)(1/2)*exp(-1/2*(R*C+(R2*C2-4*L*C)(1/2)/L/C*t)I =C*(-1/4*(R*C+(R2*C2-4*L*C)(1/2)/(R2*C2-4*L*C)(1/2)*(R*C-(R2*C2-4*L*C)(1/2)/L/C*exp(-1/2*(R*C-(R2*C2-4*L*C)(1/2)/L/C*t)+1/4*(R*C-(R2*C2-4*L*C)(1/2)/(R2*C2-4*L*C)(1/2)*(R*C+(R2*C2-4*L*C)(1/2)/L/C*exp(-1/2*(R*C+(R2*C2-4*L*C)(1/2)/L/C*t)t=0:0.1:1;R=500;L=30;C=30;Uc =1/2*(R*C+(R2*C2-4*L*C)(1/2)/(R2*C2-4*L*C)(1/2)*exp(-1/2*(R*C-(R2*C2-4*L*C)(1/2)/L/C*t)-1/2*(R*C-(R2*C2-4*L*C)(1/2)/(R2*C2-4*L*C)(1/2)*exp(-1/2*(R*C+(R2*C2-4*L*C)(1/2)/L/C*t);I =C*(-1/4*(R*C+(R2*C2-4*L*C)(1/2)/(R2*C2-4*L*C)(1/2)*(R*C-(R2*C2-4*L*C)(1/2)/L/C*exp(-1/2*(R*C-(R2*C2-4*L*C)(1/2)/L/C*t)+1/4*(R*C-(R2*C2-4*L*C)(1/2)/(R2*C2-4*L*C)(1/2)*(R*C+(R2*C2-4*L*C)(1/2)/L/C*exp(-1/2*(R*C+(R2*C2-4*L*C)(1/2)/L/C*t);plot(Uc,I)1