[求助]小学生求解问题

gdxinlan

偶是初来者，没有学过matlab，但想请教学长们问题：
已知x，y满足方程：
x=y*(1/(0.1-a*y))^a;
其中a＝2.44；x为一向量[0:0.2:5]；
怎样能求出y的值，并画图呢？
多谢！

cora

这是隐函数绘图问题，见帖子
http://forum.vibunion.com/thread-3606-1-1.html

gdxinlan

不太懂啊

suffer

调用上面连接里的子程序画图就行了

gdxinlan

请教系主任
是调用这个程序吗：可是我看不懂啊，试了一下下面这个原程序好像说有问题啊

1. function implot(fun,rangexy,ngrid)
   
2. % Implicit plot function
   
3. % function implot(fun,rangexy,ngrid)
   
4. % fun is 'inline' function f(x,y)=0 (Note function written as equal to zero)
   
5. % rangexy =[xmin,xmax,ymin,ymax] range over which x and y is ploted default(-2*pi,2*pi)
   
6. % ngrid is the number of grid points used to calculate the plot,
   
7. % Start with course grid (ngrid =20) and then use finer grid if necessary
   
8. % default ngrid=50
   
9. %
   
10. % Example
    
11. % Plot y^3+exp(y)-tanh(x)=0
    
12. %
    
13. % write function f as an 'inline' function of x and y-- right hand side
    
14. % equal to zero
    
15. %
    
16. % f=inline('y^3+exp(y)-tanh(x)','x','y')
    
17. % implot(f,[-3 3 -2 1])
    
18. % A.Jutan UWO 2-2-98 ajutan@julian.uwo.ca
    
19. 
    
20. if nargin == 1 ;% grid value and ranges not specified calculate default
    
21. rangexy=[-2*pi,2*pi,-2*pi,2*pi];
    
22. ngrid=50;
    
23. end
    
24. 
    
25. 
    
26. if nargin == 2; % grid value not specified
    
27. ngrid=50;
    
28. end
    
29. 
    
30. % get 2-D grid for x and y
    
31. 
    
32. xm=linspace(rangexy(1),rangexy(2),ngrid);
    
33. ym=linspace(rangexy(3),rangexy(4),ngrid);
    
34. [x,y]=meshgrid(xm,ym);
    
35. fvector=vectorize(fun);% vectorize the inline function to handle vectors of x y
    
36. fvalues=feval(fvector,x,y); %calculate with feval-this works if fvector is an m file too
    
37. %fvalues=fvector(x,y); % can also calculate directly from the vectorized inline function
    
38. contour(x,y,fvalues,[0,0],'b-');% plot single contour at f(x,y)=0, blue lines
    
39. xlabel('x');ylabel('y');
    
40. grid

复制代码

能讲解一下吗，谢谢指教！