i need help with my code, for error

I have an error in line 12, help pls

clc
close all

Ks=inputdlg('Ingrese valor de la rugosidad de la tuberia: ')
Re=inputdlg('Ingrese numero de Reynolds: ')
D=inputdlg('Ingrese diametro de la tuberia')

funcion=char(inputdlg('Ingrese la funcion'));    
f=inline(2*log10((Ks/3.7*D)+(2.51/Re*sqrt(log10*x)))+1/sqrt(log10*x));
x=-5:0.001:30;

n=length(x);
for i=1:n
    y(i)=f(x(i));
    
end


plot(x,t,'LineWidth',2);
hold on
plot([-5 30],[0 0],'r');
grid on;
plot([0 0],[-50 250],'r');
hold off

x1=str2double(inputdlg('ingrese el valor de x(i-1)'));
x2=str2double(inputdlg('Ingrese el valor de x(i)'));
tol=str2double(inputdlg('Ingrese error admisible en %'))

error=100;
i=1;
disp('Iter     x(i-1)     x(i)    x(i+1)     Error(%)');
hold on
while error>tol
    x3=x2-(f(x2)*(x2-x1))/(f(x2)-f(x1));
    error=abs((x3-x2)/x3)*100;
    fprintf('%2.0f %f %f   %f %f\n',i,x1,x2,x3,error)
    if f(x1)>f(x2)
        if f(x1)>0 && f(x2>0)
            hold on
            plot([x1 x3],[f(x1) 0],'m')
        end
        if f(x1)>0 && f(x2)<0
            hold on
            plot([x1 x1],[f(x1) f(x2)],'m')
        end
    end
    if f(x1)<=f(x2)
        if f(x1)>0 && f(x2)>0
            hold on
            plot([x3 x2],[0 f(x2) ],'m')
        end
        if f(x1)<0 && f(x2)>0
            hold on
            plot([x1 x2],[f(x1) f(x2)],'m')
        end
    end
    x1=x2;
    x2=x3;
    i=i+1;
end
disp('  ')
disp('solucion: ')
disp(['x= ',num2str(x3),' en ',num2str(i-1),' iteraciones '])

plot(x3,f(x3),'go','LineWidth',2)

Answer 1

[Walter Roberson]

That is the wrong syntax for inline(). inline() needs a character vector, not code.

Unless you will lose marks if you do not use inline specifically, then you should use an anonymous function instead of inline()

[Vicente Fuentealba Reyes]

but, in line 16, appears the 'Array indices must be positive integers or logical values.' error

[Vicente Fuentealba Reyes]

error in for cycle, y(i)

[Walter Roberson]

if you build the inline incorrectly then f might not end up the correct class.

Answer 2

[Sulaymon Eshkabilov]

Here are corrected part of your script:

Ks=str2double(doubleKs{:});  Re=str2double(Re{:}); D = str2double(D{:});  % Data conversion for calc's
f=@(x)(2*log10((Ks/3.7*D)+(2.51/Re.*sqrt(log10(x)))+1./sqrt(log10(x))));
x=-5:0.001:30;
n=length(x);
y=zeros(1,n);   % Memory allocation for the efficency
for i=1:n
    y(i)=f(x(i));
    
end
plot(x,y,'LineWidth',2);     % Variable t is to be y