I want it to find the solution with the Newton Raphson method with the function entered, but it gives an error and when I copy and paste the codes on another page, it pastes d

clc; clear all;
syms x
E=input('Epsilon değerini giriniz E: ');
max=20;
x0=input('X0 değerini giriniz -> ');      
f(x)=input('Fonksiyon değerini giriniz f(x):');
f1=diff(f); 
for k=1:max
    a=f1(x0);
    if abs(a)<0.00001
        disp('turevin değeri sıfıra çok yakın, algoritma durur')
        break
    end
    x1=x0-f(x0)/f1(x0);
    hata=abs(x1-x0);
    x0=x1;
    y=f(x0);
    if(abs(y)<epsilon)
        break
    end
end
disp('root')
x1;
disp('error')
y;
disp('iteration')
k;

[Jan]

"It pastes d"?!

Which error message do you get? It is very useful to know the error, if it should be fixed. I guess, this fails:

f(x)=input('Fonksiyon değerini giriniz f(x):');

"f(x)" is no valid variable, if x is a symbolical variable. Use:

f=input('Fonksiyon değerini giriniz f(x):');

And epsilon is not defined.

[Aleyna Dolar]

I wonder how to define epsilon sorry i'm new at this...

[Jan]

The value of epsilon depends on what you want. You can choose this freely as upper limit, which you accept as "almost zero".

By the way, avoid redefining built-in functions as max() as a variable. This is no error, but if you try to use the function max() later the level of confusion is high.

Answer 1

[Walter Roberson]

fstr = input('Fonksiyon değerini giriniz f(x):', 's');
syms x
fsym = str2sym(fstr);
f = matlabFunction(fsym, 'vars', x);
f1sym = diff(fsym) ;
f1 = matlabFunction(f1sym, 'vars', x) ;