Array indices must be positive integers or logical values.

clc;

clear all;

x=1;

h=10;

f = @(x) sin(((x^2+x)))

for n = 1:10

df(n-1) = (f(x+(h^(n-1)) - f(x)))/(h^n-1)

end

not sure what I am doing wrong to get this error.

Answer 1

[Johannes Fischer]

The first entry in any kind of Matlab vector/array/matrix... is indexed with 1 (and not 0, as for example in C++). That is why you get an error in the first iteration of your for loop.

Two options:

adjust the indieces for df

for n = 1:10
    df(n) = (f(x+(h^(n-1)) - f(x)))/(h^n-1);
end

or, in Matlab you can get rid or the for loop and matalb calculates the resulting array in a single line, in many cases this is faster than usinng for loops

n = 1:10;
df = (f(x+(h^(n-1)) - f(x)))/(h^n-1);