how to plot a factorial with variable please help!

I want to plot a function that contains factorial in it. But for some reason it produced many errors. The graph can be plotted if I open up the factorial and write it. But I am wondering what's wrong with with the code with factorial function.

Here's the code I am struggling with:

syms n;
f(n) = 1-factorial(3000-n)./factorial(2990-n)./(3000^10);
range = linspace(1,3000,3000);
plot(range, f(range));

This is the error message:

Error using symengine
Nonnegative integer or a symbol expected.

Error in sym/subs>mupadsubs (line 157)
G = mupadmex('symobj::fullsubs',F.s,X2,Y2);

Error in sym/subs (line 142)
  G = mupadsubs(F,X,Y);

Error in symfun/feval>evalScalarFun (line 42)
y = subs(formula(Ffun), Fvars, inds);

Error in symfun/feval (line 28)
  varargout{1} = evalScalarFun(F, Fvars, varargin);

Error in symfun/subsref (line 178)
              B = feval(A,inds{:});

Error in untitled (line 4)
plot(range, f(range));

If I open up the factorial (write out each term and run the code, it produced the desired image:

Answer 1

[Majid Farzaneh]

Hi, This will work:

syms n;
f(n) = 1-factorial(3000-n)./factorial(2990-n)./(3000^10);
range = linspace(1,2990,2990);
plot(range, f(range));

The input argument of factorial must be positive or zero (Test factorial(-1)). You have factorial(2990-n) and n=2991:3000 in your code that makes factorial undefined.

[yuqing zhu]

Thank you so much for the fast reply and solved the issue! I didn't notice the mathematical error here.

[Majid Farzaneh]

I have an another suggestion for you. This code has better performance if you can forget the syms

n = linspace(1,2990,2990);
f = 1-factorial(3000-n)./factorial(2990-n)./(3000^10);
plot(n, f);

[Majid Farzaneh]

You're welcome.