Error: Not Enough Input Arguments.

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Park
Park 2014-1-27
回答： Azzi Abdelmalek 2014-1-27
"Error using newton_mathod (line 48). Not enough input arguments" why does it give me this error message? here is my code:
function [ x, ex ] = newton_mathod(f,df,x0,tol,nmax)
syms x;
f=@(x)0.95*x^3 - 5.9*x^2 + 10.9*x - 6
df=@(x)2.85*x^2 - 11.8*x + 10.9
x0=1;
if nargin == 3
tol = 1e-4;
nmax = 1e1;
elseif nargin == 4
nmax = 1e1;
elseif nargin ~= 5
disp('newton invalid input parameters');
end
f = inline('f');
df = inline('df');
x(1) = x0 - (f(x0)/df(x0));
ex(1) = abs(x(1)-x0);
k = 2;
while (ex(k-1) >= tol) && (k <= nmax);
x(k) = x(k-1) - (f(x(k-1))/df(x(k-1)));
ex(k) = abs(x(k)-x(k-1));
k = k+1;
end
end

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回答（1 个）

Azzi Abdelmalek
Azzi Abdelmalek 2014-1-27
I don't know if you have done this code or find it somewhere. This code represent a function, but at the same time the input argument f and df are unnecessary, because they are defined inside your function
f=@(x)0.95*x^3 - 5.9*x^2 + 10.9*x - 6
df=@(x)2.85*x^2 - 11.8*x + 10.9
Then just after, they are replaced by
f = inline('f');
df = inline('df');

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