厦门大学数学科学学院：《高等代数》课程教学资源（应用与实验）Key to MATLAB Ex 9 - Graphics-Surface

Key to MATLAB Exercise 9 SchoolofMathematicalSciencesXiamenUniversityhttp://gdjpkc.xmu.edu.cn Key to MATLAB Exercise 9-Graphics-Surface >>clear; clf, xlinspace(-4, 4, 20): y=linspace(-5, 5, 20); >>(X,Y]= meshgrid(x,y);Z=0.3°eXp(-0.15°(X^2+￥^2)-0.3*eXp(0.15°(X.^2+Y.A2) > plot(X,Y, 2); grid on > mesh(X,Y,Z) B如气:日 >>surf(X,Y,z) Key to Ex9-1

Key to MATLAB Exercise 9  School of Mathematical Sciences Xiamen University  http://gdjpkc.xmu.edu.cn  Key to Ex9­1  Key to MATLAB Exercise 9 – Graphics ­Surface  1. >> clear; clf; x=linspace(­4,4,20); y=linspace(­5,5,20);  >> [X, Y]=meshgrid(x,y); Z=[0.3*exp(­0.15*(X.^2+Y.^2))­ 0.3*exp(0.15*(X.^2+Y.^2))];  1) >> plot3(X,Y,Z); grid on;  2) >> mesh(X,Y,Z) 3) >> surf(X,Y,Z)

Key to MATLAB Exercise 9 SchoolofMathematicalSciencesXiamenUniversityhttp://gdjpkc.xmu.edu.cn > mesh(X,Y, z) it- yis Atrt Taal: Detha yidan. yA > surfc(, Y, z) B点口一 >>x=(9: 9;y=[-9: 9]:(X,Y=meshgrid(x, y) >> XY=(X. 2+Y.2).(1/2)+eps; Z=sin(XY) / XY > subplot(1, 3, 1): plot(x,Y,z) > title('Display by plots function ); xlabel('x): ylabel('y); zlabel(z); grid on > subplot( 1, 3, 2); mesh(X,Y, z); > title('Display by mesh function ); xlabel('x): ylabel('y); zlabel('z'); grid on > subplot(1, 3, 3); surf(X,Y, Z > title('Display by surf function); xlabel('x); ylabel(y); zlabel('z); grid on

Key to MATLAB Exercise 9  School of Mathematical Sciences Xiamen University  http://gdjpkc.xmu.edu.cn  Key to Ex9­2  4) >> meshz(X,Y,Z) 5) >> surfc(X,Y,Z) 2.  >> clear; clf;  >> x=[­9:9];y=[­9:9]; [X,Y]=meshgrid(x,y);  >> XY= (X.^2+Y.^2).^(1/2)+eps; Z=sin(XY)./XY;  1) >> subplot(1,3,1); plot3(X, Y, Z);  >> title('Display by plots function'); xlabel('x'); ylabel('y'); zlabel('z'); grid on  2) >> subplot(1,3,2); mesh(X,Y,Z);  >> title('Display by mesh function'); xlabel('x'); ylabel('y'); zlabel('z'); grid on  3) >> subplot(1,3,3); surf(X, Y, Z);  >> title('Display by surf function'); xlabel('x'); ylabel('y'); zlabel('z'); grid on

Key to MATLAB Exercise 9 School of Mathematical Sciences Xiamen University htt kc xmu edu. cn - Figure I Eile Edit Yiew Insert Tools Desktop lindow Help 日Q回果日国日 Display by plots function Display by mesh function Display by surf function 0 y-10-10 > clear: clf >>UF[0: 0.5: 4*pi]: v=[0: 0.5: 4 pi: [U, V=meshgrid(u, v) >>X=U'cos(V): Y=U*sin(V): Z=2*U+8*V > figure(1); plot(X, Y, Z); grid on > figure(2); mesh(X, Y, 2); grid on 母回日日日口

Key to MATLAB Exercise 9  School of Mathematical Sciences Xiamen University  http://gdjpkc.xmu.edu.cn  Key to Ex9­3  3.  >> clear; clf;  >> u=[0:0.5:4*pi]; v=[0:0.5:4*pi]; [U,V]=meshgrid(u,v);  >> X=U.*cos(V); Y=U.*sin(V); Z=2*U+8*V;  1) >> figure(1); plot3(X,Y,Z); grid on  2) >> figure(2); mesh(X,Y,Z); grid on

Key to MATLAB Exercise 9 SchoolofMathematicalSciencesXiamenUniversityhttp://gdjpkc.xmu.edu.cn 3) > figure(3); surf(X,Y, 2); grid on >> clear close all >> tlinspacet(0,6),x=0.52;y=0.14^3;z=9(c08(2*t) > plot(x,y, z); grid or B点口 > theta=linspace(-pi/2, 0); leq= linspace(-pi, pi) > TTHETA, LEQImeshgrid( theta, leg) >>X=COS(THETA).sin(LEQ): Y=cos(THETA). "cos(LEQ): Z=sin(THETA) >> mesh(X, Y, Z); axis equal Key to Ex9-4

Key to MATLAB Exercise 9  School of Mathematical Sciences Xiamen University  http://gdjpkc.xmu.edu.cn  Key to Ex9­4  3) >> figure(3); surf(X,Y,Z); grid on  4.  >> clear; close all;  >> t=linspace(0,6); x=0.5*t.^2; y=0.1*t.^3; z=9*( cos(2*t));  >> plot3(x,y,z); grid on  5.  >> theta=linspace(­pi/2,0); leq=linspace(­pi,pi);  >> [THETA,LEQ]=meshgrid(theta,leq);  >> X=cos(THETA).*sin(LEQ);Y=cos(THETA).*cos(LEQ); Z=sin(THETA);  >> mesh(X,Y,Z); axis equal;

Key to MATLAB Exercise 9 SchoolofMathematicalSciencesXiamenUniversityhttp://gdjpkc.xmu.edu.cn >> t=pi/16: pi/8: 2* pl; x=cos(t): y=sin(t) >> fill(x,y;b), axis square;tite正十六边形) Eil. Eit yie Last tault Desktop Yiadww wall ≥日A我回日目口口 > phi=pi/2: 4 pi/5: 4 pi; B=exp(i phi): xl=real(B); yl=imag(B) ttle五角星) 國: and(10,1)*10;V=rand(10,1)*10

Key to MATLAB Exercise 9  School of Mathematical Sciences Xiamen University  http://gdjpkc.xmu.edu.cn  Key to Ex9­5  6.  >> t=pi/16: pi/8:2*pi; x=cos(t);y=sin(t);  >> fill(x,y,'b'); axis square; title('正十六边形') 7.  >> phi=pi/2:4*pi/5:4*pi; B=exp(i*phi); x1=real(B); y1=imag(B);  >> fill(x1,y1,'r'),axis square; title('五角星') 8.  >> u=rand(10,1)*10; v=rand(10,1)*10;

Key to MATLAB Exercise 9 SchoolofMathematicalSciencesXiamenUniversityhttp://gdjpkc.xmu.edu.cn >>xu. cos(v); y=u. sin(v): Z=2 u+2V >>xlin=linspace(min(x), max(x), 33) > yin= linspace(min(y), max(y), 33) shgrid(xlin, lin) >>Z=griddata(x,y, z, X,Y,cubic) >>mesh(X,Y, z) > axis tight; hold on plot(x, y, z, ., MarkerSize, 15) Key to Ex9-6

Key to MATLAB Exercise 9  School of Mathematical Sciences Xiamen University  http://gdjpkc.xmu.edu.cn  Key to Ex9­6  >> x=u.*cos(v); y=u.*sin(v); z=2*u+2*v;  >> xlin = linspace(min(x),max(x),33);  >> ylin = linspace(min(y),max(y),33);  >> [X,Y] = meshgrid(xlin,ylin);  >> Z = griddata(x,y,z,X,Y,'cubic');  >> mesh(X,Y,Z) >> axis tight; hold on  >> plot3(x,y,z,'.','MarkerSize',15)