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function xx=fseries(funfcn,a,b,n,tol,p1,p2,p3) 
%FSERIES    Returns the Fourier series coefficients. 
%       XX=FSERIES(FUNFCN,A,B,N,TOL,P1,P2,P3) 
%       funfcn=the given function, in an m-file. 
%       It can depend on up to three parameters 
%       p1,p2, and p3. The function is given 
%       over one period extending from 'a' to 'b' 
%       xx=vector of length n+1 of Fourier Series 
%       Coefficients, xx0,xx1,...,xxn. 
%       p1,p2,p3=parameters of funfcn.  
%       tol=the error level. 
 
j=sqrt(-1); 
args0=[]; 
for nn=1:nargin-5 
  args0=[args0,',p',int2str(nn)]; 
end 
args=[args0,')']; 
t=b-a; 
xx(1)=eval(['1/(',num2str(t),').*quad(funfcn,a,b,tol,[]',args]) ; 
 
for i=1:n 
  new_fun = 'exp_fnct' ; 
  args=[',', num2str(i), ',', num2str(t), args0, ')' ] ; 
  xx(i+1)=eval(['1/(',num2str(t),').*quad(new_fun,a,b,tol,[],funfcn',args]); 
end