Using the find function

Question

Denikka Brent 2018-11-11

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/429175-using-the-find-function

评论： madhan ravi 2018-11-11

I am trying to pull out a certain value in this function. I am trying to find the values of the wbar(i,1),wbar(i,2), and wbar(i,3) each at M=0,0.5,1,and 5. I can get it to work at M=0 and M=5 but not between. Can anyone help with this?

Here is my code:

n = 100;
M = linspace(0,5,n);
wbar = NaN(n,3);
wbar(1,:) = [pi/2,3*pi/2,5*pi/2];
for i=2:n
    fun = @(w) cos(w) - M(i)*sin(w);
      wbar(i,1) = fzero(fun,wbar(i-1,1));
      wbar(i,2) = fzero(fun,wbar(i-1,2));
      wbar(i,3) = fzero(fun,wbar(i-1,3));
  end
  figure(1)
  plot(M,wbar,'-')
  grid on
index = find(M==2);
freq1=wbar(index,1)
index = find(M==2);
freq2=wbar(index,2)
index = find(M==2);
freq3=wbar(index,3)