11.txt

1． 在No.1图形窗口中绘制 y=sin(x)在[0,2*pi]内的曲线。要求曲线的颜色为绿色

clc; 
clear; 
f=figure(6); 
x=0:0.1:2*pi; 
y=sin(x); 
l=plot(x,y); 
a=gca; 
gf=get(f); 
gl=get(l); 
ga=get(a); 
gt=get(a,'title'); 
haha=get(gt) 
set(gt,'string','正弦函数'); 
gc=get(l,'color') 
set(l,'color',[1,0,0])  
 
 clc 
figure(1) 
x=0:0.1*pi:2*pi; 
y=sin(x); 
plot(x,y,'-*g'); 
axis ('equal'); 
grid on; 
title('正弦函数'); 
xlabel('X轴','FontName','黑体'); %第一题 
figure(2) 
x=0:0.1*pi:2*pi; 
subplot(2,2,1); 
plot(x,x.^2,'-*r',x,-x.^2,'-ob',x,x.^2.*sin(x),'-^m'); 
title('y=x^2'); 
subplot(2,2,2); 
plot(x,-x.^2,'-ob'); 
title('y=-x^2'); 
subplot(2,2,3); 
plot(x,x.^2.*sin(x),'-^m'); 
title('y=x^2*sin(x)'); 
subplot(2,2,4); 
t=0:0.1*pi:2*pi; 
x=sin(t); 
y=cos(t); 
plot3(x,y,t,'g'); 
title('3D image'); %第二题 
figure(3) 
subplot(2,3,1); 
[x,y]=meshgrid(-5:0.2:5,-5:0.2:5); 
plot3(x,y,x.*exp(-x.^2-y.^2)); 
title('plot3'); 
subplot(2,3,2); 
[X,Y]=meshgrid([-5:0.2:5]); 
Z=X.*exp(-X.^2-Y.^2); 
mesh(Z); 
title('mesh'); 
subplot(2,3,3); 
[X,Y]=meshgrid([-5:0.2:5]); 
Z=X.*exp(-X.^2-Y.^2); 
meshc(Z); 
title('meshc'); 
subplot(2,3,4); 
[X,Y]=meshgrid([-5:0.2:5]); 
Z=X.*exp(-X.^2-Y.^2); 
meshz(Z); 
title('meshz'); 
subplot(2,3,5); 
[X,Y]=meshgrid([-5:0.2:5]); 
Z=X.*exp(-X.^2-Y.^2); 
surf(Z); 
light('position',[1,0.5,2]); 
colormap(spring); 
title('surf'); %第三题 

figure(4) 
[X,Y]=meshgrid(-8:0.1:8,-10:0.1:10); 
Z=sin(X.*Y)+cos(X.*Y); 
meshz(Z);  
 function f=lsq() 
x=[1978:2005]; 
y=[9.5416 9.6996 9.8573 10.014 10.171 10.327 10.482 10.636 10.790 10.942 11.093 11.243 11.392 11.540 11.686 11.830 11.973 12.115 12.255 12.393 12.529 12.663 12.796 12.927 13.055 13.182 13.315 13.330]; 
canshu=[20,3,2,1900]; 
canshu=lsqcurvefit('func1',[20,3,2,1970],x,y) 
xx=[1978:2020]; 
yy=canshu(1)./(1+canshu(2).*exp(-canshu(3).*(xx-canshu(4)))); 
plot(xx,yy,'r') 
yw=canshu(1)./(1+canshu(2).*exp(-canshu(3).*(x-canshu(4)))); 
norm(yw-y) %误差 
xy=[2006:2020]; 
yy=canshu(1)./(1+canshu(2).*exp(-canshu(3).*(xy-canshu(4)))) %2020年前的人口总数  
 
 function f=pingfang() 
x=[1978:2005]; 
y=[9.5416 9.6996 9.8573 10.014 10.171 10.327 10.482 10.636 10.790 10.942 11.093 11.243 11.392 11.540 11.686 11.830 11.973 12.115 12.255 12.393 12.529 12.663 12.796 12.927 13.055 13.182 13.315 13.330]; 
n=27; 
xx1=0; 
for i=1:27 
 xx1=xx1+y(i)^0; 
end 
xx2=0; 
for i=1:27 
 xx2=xx2+y(i)^1; 
end 
xx3=0; 
for i=1:27 
 xx3=xx3+y(i)^2 
end 
yy1=0; 
for i=1:27 
 yy1=yy1+(y(i+1)-y(i)); 
end 
yy2=0; 
for i=1:27 
 yy2=yy2+(y(i+1)-y(i))*y(i); 
end 
A=[xx1 xx2;xx2 xx3]; 
b=[yy1;yy2]; 
c=A\b;