同济大学matlab课程练习题答案

同济大学matlab课程练习题答案关晓飞第一章 初识matlab题目1x1=input(x1=);x2=input(x2=);x3=input(x3=);x4=input(x4=);x5=input(x5=);x6=input(x6=);x7=input(x7=);a=x1/x5;b=x3/(x2-x1)0.85;c=1-0.36*(x4/x2)(-0.56);d=2.62*c1.5;e=(x4/x2)1.16;f=(1-d*e)/(x6*x7)0.5;y=174.42*a*b*f题目2略题目3 help lookfor lookfor Search all MATLAB files for keyword. lookfor XYZ looks for the string XYZ in the first comment line (the H1 line) of the HELP text in all MATLAB files found on MATLABPATH (including private directories). For all files in which a match occurs, lookfor displays the H1 line. For example, lookfor inverse finds at least a dozen matches, including the H1 lines containing inverse hyperbolic cosine two-dimensional inverse FFT, and pseudoinverse. Contrast this with which inverse or what inverse, which run more quickly, but which probably fail to find anything because MATLAB does not ordinarily have a function inverse. lookfor XYZ -all searches the entire first comment block of each MATLAB file. In summary, WHAT lists the functions in a given directory, WHICH finds the directory containing a given function or file, and lookfor finds all functions in all directories that might havesomething to do with a given key word.题目4n=input(n=);sum(1:n)prod(1:n)题目5 linspace(0,360,9) ans = 0 45 90 135 180 225 270 315 360题目7n=input(n=)format bankn第二章矩阵的建立题目1.spiral产生螺旋矩阵例：spiral(3)ans= 7 8 9 6 1 2 5 4 3题目2.（1）1 2;3 4+10-2ians = 11.0000 - 2.0000i 12.0000 - 2.0000i 13.0000 - 2.0000i 14.0000 - 2.0000i（2）1 2;3 4.*0.1 0.2;0.3 0.4ans = 0.1000 0.4000 0.9000 1.6000（3）1 2;3 4.20 10;9 2ans = 20.0000 5.0000 3.0000 0.5000（4）exp(1 2;3 4) %自然对数的1、2、3、4乘方ans = 2.7183 7.3891 20.0855 54.5982（5）1 2;3 4.2ans = 1 4 9 16（6）sum(1 2;3 4) ans = 4 6（7）prod(1 2;3 4) %每一列的所有行相加ans = 3 8（8）a,b=min(10 20;30 40) %a代表每一列的最小值，b代表该值所在的行数a = 10 20b = 1 1（9）abs(1 2;3 4-pi) %绝对值ans = 2.1416 1.1416 0.1416 0.8584（10）linspace(3,4,5) %生成3到4均匀的5个数ans = 3.0000 3.2500 3.5000 3.7500 4.0000（11）A=1 2;3 4;sort(A(:,2) %提取第2列ans = 2 4题目3.A=1,2,3,4;4,3,2,1;2,3,4,1;3,2,4,1A = 1 2 3 4 4 3 2 1 2 3 4 1 3 2 4 1A(5,6)=5A = 1 2 3 4 0 0 4 3 2 1 0 0 2 3 4 1 0 0 3 2 4 1 0 0 0 0 0 0 0 5题目4示例：A=3 -1;-1 3A = 3 -1 -1 3X,D=eig(A)X = -0.7071 -0.7071 -0.7071 0.7071D = 2 0 0 4题目5A = 3 -1 -1 32Aans = 10 -6 -6 102.Aans = 8.0000 0.5000 0.5000 8.0000题目6（1）A=magic(6)A = 35 1 6 26 19 24 3 32 7 21 23 25 31 9 2 22 27 20 8 28 33 17 10 15 30 5 34 12 14 16 4 36 29 13 18 11c=A(2,1)c = 3（2）t = 2:2:6;B = A(t,:);BB = 3 32 7 21 23 25 8 28 33 17 10 15 4 36 29 13 18 11（3）A(: , end,2:end-1,1)ans = 24 1 6 26 19 35 25 32 7 21 23 3 20 9 2 22 27 31 15 28 33 17 10 8 16 5 34 12 14 30 11 36 29 13 18 4（4）A(:,1 3 4 5 6)ans = 35 6 26 19 24 3 7 21 23 25 31 2 22 27 20 8 33 17 10 15 30 34 12 14 16 4 29 13 18 11题目7ones(4,5)ans = 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1rand(3,4)ans = 0.8147 0.9134 0.2785 0.9649 0.9058 0.6324 0.5469 0.1576 0.1270 0.0975 0.9575 0.9706 eye(3)ans = 1 0 0 0 1 0 0 0 1题目8A=0:99;A=reshape(A,10,10)A = 0 10 20 30 40 50 60 70 80 90 1 11 21 31 41 51 61 71 81 91 2 12 22 32 42 52 62 72 82 92 3 13 23 33 43 53 63 73 83 93 4 14 24 34 44 54 64 74 84 94 5 15 25 35 45 55 65 75 85 95 6 16 26 36 46 56 66 76 86 96 7 17 27 37 47 57 67 77 87 97 8 18 28 38 48 58 68 78 88 98 9 19 29 39 49 59 69 79 89 99A=magic(3)题目9A = 8 1 6 3 5 7 4 9 2A(2,:)=A(2,:)*2A = 8 1 6 6 10 14 4 9 2A(1,:)=A(1,:)+A(3,:)*(-2)A = 0 -17 2 6 10 14 4 9 2题目10A=1,3,5;5,8,3;6,1,6;B=3,6;9,5;8,2;C=3,3,9;4,0,6;D=2:6;A,Bans = 1 3 5 3 6 5 8 3 9 5 6 1 6 8 2A;Cans = 1 3 5 5 8 3 6 1 6 3 3 9 4 0 6A,B;Dans = 1 3 5 3 6 5 8 3 9 5 6 1 6 8 2 2 3 4 5 6A=ones(6,7)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 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1题目11for i=1:6for j=1:7A(i,j)=i+j;endendAA = 2 3 4 5 6 7 8 3 4 5 6 7 8 9 4 5 6 7 8 9 10 5 6 7 8 9 10 11 6 7 8 9 10 11 12 7 8 9 10 11 12 13%本题还有多种方法第三章符号计算题目1略题目2 sym(0,3) ans = 0.3 sym(0.3)%符号工具箱得出更精确的解 ans = 3/10题目3 syms x s f=x5+3*x4+4*x3+2*x2+3*x+6;g=(s-1)/(s+1); f(x)=compose(f,g,x,s) f(x) = (3*(s - 1)/(s + 1) + (2*(s - 1)2)/(s + 1)2 + (4*(s - 1)3)/(s + 1)3 + (3*(s - 1)4)/(s + 1)4 + (s - 1)5/(s + 1)5 + 6 simplify(f(x)ans = 19 - (72*s4 + 120*s3 + 136*s2 + 72*s + 16)/(s + 1)5题目4 sum(sym(2).1:64) ans = 36893488147419103230题目5f=sym(cos(4*a)-4*cos(2*a)+3);simplify(f) ans = 8*sin(a)4题目6 f=sym(3*x+2/3)10);expand(f) ans = 59049*x10 + 131220*x9 + 131220*x8 + 77760*x7 + 30240*x6 + 8064*x5 + (4480*x4)/3 + (5120*x3)/27 + (1280*x2)/81 + (5120*x)/6561 + 1024/59049所以系数最大的项是131220*x9 和 131220*x8题目7 syms a x factor(a*(sin(x)2-(2*a2-a+1)*sin(x)+2*a-1) ans = (sin(x) - 2*a + 1)*(a*sin(x) - 1)第四章极限与导数题目1（1） syms x;lim1=limit(cos(x)-exp(-x2/2)/x4,x,0)lim1 =-1/12（2） syms x t;lim2=limit(1+2*t/x)3*x,x,inf)lim2 =Inf + imag(t)*6*i（3） syms x;lim3=limit(1/x,x,0,right)Lim3 =Inf（4） syms x;lim4=limit(2x-log(2x)-1)/(1-cos(x),x,0)Lim4 =log(2)2题目2 syms x;lim=limit(exp(x)-1-x)/x2,x,0)lim =1/2题目3 syms x;lim=limit(x0.5-2(-1/x),x,0,right)lim =0题目4 syms x;lim=limit(atan(x)/(1+x2),x,pi,left)lim =atan(pi)/(pi2 + 1)题目5 y=7*x3-2*x+3;z=diff(y,2);x=1;eval(z)ans =42题目6 syms x y;z=exp(x)*sin(2*y)+log(x)*cos(2*y);f=diff(z,y)f =2*cos(2*y)*exp(x) - 2*sin(2*y)*log(x)题目7 syms x y t;x=t2*sin(t);y=2*t*cos(t);f=diff(y)/diff(x)f =(2*cos(t) - 2*t*sin(t)/(t2*cos(t) + 2*t*sin(t)题目8 syms x;lim=limit(3x+9x)(1/x),x,inf)lim =9题目9 syms x;lim=limit(1+x)(1/x),x,0)lim =exp(1)题目10 syms x;y=(x-1)*(x-2)/(x-3)/(x-4)0.5;f1=diff(y,1),f2=diff(y,2),f3=diff(y,3)f1 =(x - 1)/(x - 3)*(x - 4) + (x - 2)/(x - 3)*(x - 4) - (x - 1)*(x - 2)/(x - 3)*(x - 4)2) - (x - 1)*(x - 2)/(x - 3)2*(x - 4)/(2*(x - 1)*(x - 2)/(x - 3)*(x - 4)(1/2)f2 =(2/(x - 3)*(x - 4) - (2*(x - 1)/(x - 3)*(x - 4)2) - (2*(x - 1)/(x - 3)2*(x - 4) - (2*(x - 2)/(x - 3)*(x - 4)2) - (2*(x - 2)/(x - 3)2*(x - 4) + (2*(x - 1)*(x - 2)/(x - 3)*(x - 4)3) + (2*(x - 1)*(x - 2)/(x - 3)2*(x - 4)2) + (2*(x - 1)*(x - 2)/(x - 3)3*(x - 4)/(2*(x - 1)*(x - 2)/(x - 3)*(x - 4)(1/2) - (x - 1)/(x - 3)*(x - 4) + (x - 2)/(x - 3)*(x - 4) - (x - 1)*(x - 2)/(x - 3)*(x - 4)2) - (x - 1)*(x - 2)/(x - 3)2*(x - 4)2/(4*(x - 1)*(x - 2)/(x - 3)*(x - 4)(3/2)f3 =(3*(x - 1)/(x - 3)*(x - 4) + (x - 2)/(x - 3)*(x - 4) - (x - 1)*(x - 2)/(x - 3)*(x - 4)2) - (x - 1)*(x - 2)/(x - 3)2*(x - 4)3)/(8*(x - 1)*(x - 2)/(x - 3)*(x - 4)(5/2) - (6/(x - 3)*(x - 4)2) + 6/(x - 3)2*(x - 4) - (6*(x - 1)/(x - 3)*(x - 4)3) - (6*(x - 1)/(x - 3)2*(x - 4)2) - (6*(x - 1)/(x - 3)3*(x - 4) - (6*(x - 2)/(x - 3)*(x - 4)3) - (6*(x - 2)/(x - 3)2*(x - 4)2) - (6*(x - 2)/(x - 3)3*(x - 4) + (6*(x - 1)*(x - 2)/(x - 3)*(x - 4)4) + (6*(x - 1)*(x - 2)/(x - 3)2*(x - 4)3) + (6*(x - 1)*(x - 2)/(x - 3)3*(x - 4)2) + (6*(x - 1)*(x - 2)/(x - 3)4*(x - 4)/(2*(x - 1)*(x - 2)/(x - 3)*(x - 4)(1/2) - (3*(x - 1)/(x - 3)*(x - 4) + (x - 2)/(x - 3)*(x - 4) - (x - 1)*(x - 2)/(x - 3)*(x - 4)2) - (x - 1)*(x - 2)/(x - 3)2*(x - 4)*(2/(x - 3)*(x - 4) - (2*(x - 1)/(x - 3)*(x - 4)2) - (2*(x - 1)/(x - 3)2*(x - 4) - (2*(x - 2)/(x - 3)*(x - 4)2) - (2*(x - 2)/(x - 3)2*(x - 4) + (2*(x - 1)*(x - 2)/(x - 3)*(x - 4)3) + (2*(x - 1)*(x - 2)/(x - 3)2*(x - 4)2) + (2*(x - 1)*(x - 2)/(x - 3)3*(x - 4)/(4*(x - 1)*(x - 2)/(x - 3)*(x - 4)(3/2)题目11 syms x;y=x*log(x);diff(y,10)ans =40320/x9题目12 syms x;y=exp(-2*x);taylor(y,x,0,order,6)ans =- (4*x5)/15 + (2*x4)/3 - (4*x3)/3 + 2*x2 - 2*x + 1题目13 syms x;y=x/sin(x);f=taylor(y,x,2,order,5),ezplot(f)f =(2*(cos(2)2/sin(2)2 + 1/2)/sin(2) - cos(2)/sin(2)2)*(x - 2)2 - (cos(2)/(3*sin(2) + (cos(2)*(cos(2)2/sin(2)2 + 1/2)/sin(2)/sin(2) - (2*(cos(2)2/(3*sin(2)2) + (cos(2)*(cos(2)/(3*sin(2) + (cos(2)*(cos(2)2/sin(2)2 + 1/2)/sin(2)/sin(2) + 5/24)/sin(2)*(x - 2)4 - (2*cos(2)/sin(2)2 - 1/sin(2)*(x - 2) - (x - 2)3*(2*(cos(2)/(3*sin(2) + (cos(2)*(cos(2)2/sin(2)2 + 1/2)/sin(2)/sin(2) - (cos(2)2/sin(2)2 + 1/2)/sin(2) + 2/sin(2)题目14 syms x1 x2 x3 x4 x5 x6 x7;a=x1/x5;b=x3/(x2-x1)0.85;c=1-0.36*(x4/x2)(-0.56);d=2.62*c1.5;e=(x4/x2)1.16;f=(1-d*e)/(x6*x7)0.5;y=174.42*a*b*f; f1=diff(y,x1);f2=diff(y,x2);f3=diff(y,x3);f4=diff(y,x4);f5=diff(y,x5);f6=diff(y,x6);f7=diff(y,x7);x1=0.1;x2=0.3;x4=0.1;x5=1.5;x6=16;x7=0.75; eval(f1),eval(f2),eval(f3),eval(f4),eval(f5),eval(f6),eval(f7)ans =(9818671183655279594565911892649*x3)/(148552804714245632987894906880*(5*x3)(3/20) + (7003944643125492063*(5*x3)(17/20)/225179981368524800ans =(1576923169262824*(5*x3)(17/20)/651563676165967 - (9818671183655279594565911892649*x3)/(148552804714245632987894906880*(5*x3)(3/20)ans =1090091481931763/(82463372083200*(5*x3)(3/20)ans =-(61500003601250128*(5*x3)(17/20)/8470327790157571ans =-(2334648214375164021*(5*x3)(17/20)/1125899906842624000ans =-(13489104037805899137*(5*x3)(17/20)/138777850513941643264ans =-(13489104037805899137*(5*x3)(17/20)/6505211742841014272第五章 程序编制题目1略题目2function f=fib(n)if n=1|n=2 %“|”是或者 f=1;else f=fib(n-1)+fib(n-2);end题目3function a=countwords(s)d=length(s);n=1;x=0;while n0)&(isempty(ounce)=1)&(isempty(kerra)=1)ounce=kilogram*1000/28.3495,kerra=kilogram*1000/0.2,endif ounce0&(isempty(kilogram)=1)&(isempty(kerra)=1)kilogram=ounce*28.3495/1000,kerra=ounce*5*28.3495endif kerra0&(isempty(ounce)=1)&(isempty(kilogram)=1)ounce=kerra/(5*28.3495),kilogram=kerra/5000,end%每次输入其中一个，输出另两个的换算结果题目5y=input(enter a year:);m=input(enter a month:);if (mod(y,400)=0)|(mod(y,4)=0)&(mod(y,100)=0)switch m, case1,3,5,7,8,10,12 nday=31; 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