problem in plot of given equation

df=1:300;

nc=1.33;

ns=1.5;

nf=1.59;

theta=10:60

y=zeros(length(theta),length(df))

x=1.5*sind(theta);

l=632.8;

zfc=(l/2*pi)*sqrt(x.^2-nc.^2);

zfs=(l/2*pi)*sqrt(x.^2-ns.^2);

p=1;

de=df+zfc+zfs

y=(nc/x)*((nf^2-x^2)./(nf^2-nc^2))*(zfc/de)*(2*(x/nc)^2-1)^p;

plot(df,y)

iI have problem to plot the graph

[M.MUSBA Elhadid]

The sizes of vectors that are input arguments to plot function have to be the same. So you have to check it.

Answer 1

[Abhaya]

Hi Shiv,

The error you are encountering occurs while adding the vectors‘df’,‘zfc’, and‘zfs’, which have different sizes. Specifically, the vector‘df’is of size 1x300, while‘zfc’and‘zfs’are calculated based on the vector‘theta’, which is of a size 1x51. To resolve this issue, you can make vector‘theta’of size 1x300 using MATLAB‘linspace’function.

theta=linspace(10,60,300); 

Additionally, when calculating 'y', ensure that you are using element-wise operations to handle each element of the vectors individually. The code given below shows how you can assign values to ‘y’:

y=(nc./x).*((nf^2-x.^2)./(nf^2-nc^2))*(zfc/de).*(2*(x/nc).^2-1).^p; 

Please refer to the code snippet given below, to resolve the error.

df = 1:300; 
nc = 1.33; 
ns = 1.5; 
nf = 1.59; 

% adjust theta to match the size of df 
theta = linspace(10, 60, 300);  

x = 1.5 * sind(theta); 
l = 632.8; 
zfc = (l / (2 * pi)) * sqrt(x.^2 - nc.^2); 
zfs = (l / (2 * pi)) * sqrt(x.^2 - ns.^2); 
p = 1; 

% ensure df, zfc, and zfs are compatible in size 
de = df + zfc + zfs; 

% using element-wise operations to handle each element of the vectors individually 
y = (nc ./ x) .* ((nf^2 - x.^2) ./ (nf^2 - nc^2)) .* (zfc ./ de) .* (2 * (x ./ nc).^2 - 1).^p; 

plot(df, y); 

For more information on ‘linspace’, please follow the MATLAB documentation for ‘linspace’ function.

https://www.mathworks.com/help/releases/R2021b/matlab/ref/linspace.html

Hope this helps.