I cannot detect an error on Newton Method.

I am programming the Newton Method, but I doesn´t work. Someone could help me. I would really appreciate it.

I also want to plot the function but it does not work either.

I did the following:

x = a:0.01:x+10

plot (x,f(x))

And it did not work, because no graphic appeared.

I attached the code.

Answer 1

[VBBV]

function [x,n,error] = NewtonRaphson(f,a,eps_f,eps_x,df,maxits)
                                                   %>> df 
% remaining code                                                   
x = a:0.01:x+10
plot (x,f(x))
end

Pass the anonymous function df into function NewtonRaphson

[VBBV]

Or you can plot it outside the function as below

[x,n,error] = NewtonRaphson(f,a,eps_f,eps_x,df,maxits)
x = a:0.01:x+10;
plot (x,f(x))

%--------------------------------------------------->> df as argument
function [x,n,error] = NewtonRaphson(f,a,eps_f,eps_x,df,maxits)
% code 
end

[llucia]

thanks a lot, that was what I needed! Regarding the "plot" part, should I write X instead of x when defining the x = a:0.01:x+10?