MATLAB: How to plot a 2D graph using all the for loop values

integrationMATLAB

Hi, I have the following equation to be plotted in Matlab:

***************
alp=1;
K=1;
E0=1;
for w=-20:1:20;
a=K*(cos(pi*alp/2)*w^alp+w^(2*alp));
b=1+2*(cos(pi*alp/2)*w^alp+w^(2*alp));
c=a/b;
E(w)=E0*(1+c);
end
figure(1)
plot(E,w)
xlabel('w');
ylabel('E');
title('Plot of E vs w')
*********

Can anyone tell me what is wrong in the above code, as I am unable to get the plot.

Thanking You!

Best Answer

Your errors:

you can not use a negative index
when you write for w=-20:20, at the end of the loop w=20, is just one value
you should use plot (w,E) instead of plot(E,w)

alp=1;
K=1;
E0=1;
E=[];
for w=-20:1:20;
  a=K*(cos(pi*alp/2)*w^alp+w^(2*alp));
  b=1+2*(cos(pi*alp/2)*w^alp+w^(2*alp));
  c=a/b;
    E(end+1)=E0*(1+c);
end
figure(1)
w=-20:20
plot(w,E)
xlabel('w');
ylabel('E');
title('Plot of E vs w')t(E,w)

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MATLAB: How to join points on MATLAB plot

I've gone through and vectorized your code (taken out the for loops); this will help it to run faster. The plot command now joins the points with lines.

m=50; 
c=2*10^3; 
k=2*10^7; 
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Kc=3.5*10^8; 
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v=1.784; %v=pi*D*N/60; % %Was 1.784 mean value; 
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b_lim = -1000./(2*Kc*G);
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MATLAB: How to plot using all the for loop values

You have to use: k(P) instead of k

syms x
C=1;D=1;E=1;N=1;W=1;
alp=1;
z=1;
for P=1:1:20
  aa=(sqrt(-1))*(C-P);
  b=(D-(sqrt(-1))*(P+x));
  c=(E+(sqrt(-1))*(N-P));
  d=(W^2+x.^2);
  e=b*c*d;
  f=a/e;
  S=alp*(int(f,-inf,inf));
    out = vpa(S);
    k(P)=double(out)
end
plot(abs(k))

Best Answer

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