Matlab plots only one point

I want to plot the function Y = X^m/(5^m + X^m) on a Y vs. X graph for different values of m, and I used the code below but MATLAB plots only one point. Can someone help me?

for m = 1:10
      X = linspace(1, 100, 1001);
      Y = (X.^m) / (5^m + X.^m);
      plot(X, Y);
end

Thanks!

Answer 1

[Guillaume]

You're performing matrix division instead of elementwise division. Use ./ instead of / in your Y calculation.

Once that's fixed, you'll get one plot and only one, because by default plot erases previous plots. Use hold on to prevent that.

Also note that since X doesn't change with m, it'll be faster to only calculate it once, outside the loop. So:

figure;
hold on;
X = linspace(1, 100, 1001);
for m = 1:10
      Y = (X.^m) ./ (5^m + X.^m);
      plot(X, Y);
end

edit: also note that you can avoid the loop entirely (and the need for hold on):

figure;
X = linspace(1, 100, 1001);
m = (1:10)';  %as a vector in a different direction than X
Y = (X.^m) ./ (5.^m + X.^m);  %requires R2016b or later
plot(X, Y);

[positron96]

Oh wow! That explains so much. Thank you very much! I really appreciate your help.

[positron96]

Can you tell me what the apostrophe is for in m = (1:10)' ? Thanks in advance!

[Guillaume]

As the comment says, it's to ensure that m is in a different direction than X. It makes m as a column vector, whereas X is a row vector.

That's what makes the next line work.

Answer 2

[KSSV]

X = linspace(1, 100, 1001) ;
figure
hold on
for m = 1:10
      Y = (X.^m). / (5^m + X.^m);
      plot(X, Y);
end