Error using input Unrecognized function or variable 'x'. Error in untitled (line 2) f1=input('fonksiyonu giriniz: ')

clc;
fprintf('SECANT METODU\n')
u = input('fonksiyonu girin: ','s');
f = str2func(['@(x)' u]);
x0=input('x0 noktasını giriniz: ');
x1=input('x1 noktasını giriniz: ');
e=input('toleransı giriniz: ');
n=input('iterasyonu giriniz: ');
for i=1:n
    x2 = (x0*f(x1)-x1*f(x0))/(f(x1)-f(x0));
    fprintf('x%d = %.50f/n',i,x2);
    if abs(x2-x1)<e
        break
    end
    x0 = x1;
    x1 = x2;
end

[Aleyna Dolar]

doesn't recognize lnx

Answer 1

[Cris LaPierre]

It may be in part how you are formatting your input equation, but the main problem is that there is no 'lnx' function in MATLAB. You probably mean ln(x), but that is also incorrect. In MATLAB, the natural log is log.

Your input, then, should be log(x)

For , use log10.

[Aleyna Dolar]

I understand, thank you very much

[Walter Roberson]

For future reference:

I looked through a number of different programming languages last year. In nearly all of them that I could find, the natural log was either log() or Log[] . I think I found one lesser-used programming language that used ln() -- it does show up, but in practice it is considerably less common than log