Has to be postive integer or logical.

Attempted to access t(0); index must be a positive integer or logical.

I'm trying to make it that as t is 0, the value is a given input "a". Here's my code:

function y = mynewton(f,a,n)

t(0)=a;

for i=[0:n]

t(i+1)=t(i-1)-f(t(i-1))/diff(f(x),t(i-1));

end

y=t;

[per isakson]

Matlab indexing is one-based by design

Answer 1

[Wayne King]

MATLAB indexes from 1, not 0 like C, so you must do

 t(1) = a;

and then in your for loop, you cannot start from 1, because you attempt to access t(i-1) and f(i-1). Starting from i = 1, this would error.

Also, I'm not sure what you're trying to do with f(x). MATLAB will not understand what you mean by f(x), that is human notation for doing math.

It looks like you are trying to do numerical computation, not symbolic, in which case f will be a vector. You have to address elements of a vector by using meaningful indices from 1 to the length of the vector.

[Andy]

Thank you so much for help me out.