Printing a variable inside a while loop

I'm trying to print rt, which is the time when the voltage reaches 27.4643, but it won't print anything. I think there's a problem inside the while or there's something wrong with the if. Basically, how can I make it print rt?

t=[0:0.5:100];
while (Vr>Vf)
    V=Vo*exp(-t/(R*C));
    I=Io*exp(-t./(R*C));
    Q=Qo*exp(-t./(R*C));
    U=Uo*exp(-2*t./(R*C));
    Vr=V;
    if(V==27.4643)
        rt=-R*C*(log(V/Vo)); %ecuación diferencial despejada para obtener tiempo
        disp(rt)
    end
end  

Answer 1

[Ameer Hamza]

The value will probably never become exactly equal to 27.4643. You need to define some tolerance limits for this comparison.

if(abs(V-27.4643)<0.5)

If the value of V is within 0.5 of 27.4643, the condition will become true. Adjust the tolerance values according to your requirement.

[Natalia Oñate Gomez]

Thank you, that was really useful.

[Ameer Hamza]

I am glad to be of help.