derivitive matlab temp function

in matlab how would I ask the user to enter a starting guess V0 to use as the first value for the Newton-Raphson method. If this guess causes the derivative of the temperature function to be zero , the method will immediately fail due to a division by zero. Che

[Aquatris]

You require an additional input to your function.

function y = fun(v,v0)
    %The Newton Raphson Method 
    ...
    %check condition for division by 0 
    if statement == 0
        error('Division by 0 detected, stopping the function');
    end
    % continue the method
    ...
end

What exactly is the problem you are running into?

[matt noman]

I don't know if I should write a user defined function or write the code directly into my script file

[Aquatris]

Both would work fine. script would be easier IMO. You can also find some example functions in the fileexchange