Not able to run a code given in documentation of tf function

I am trying to use the 'tf' function to get a transfer function however something seems to be wrong as I am just not able to use the function without an error about index popping up. I even tried this code given in the examples in documentation of the 'tf' function:

numerator = 1;

denominator = [2,3,4];

sys = tf(numerator,denominator)

And I get the error: Index in position 2 exceeds array bounds (must not exceed 1).

Can someone please help me? This is frustrating.

Answer 1

[madhan ravi]

clear tf

[Niket Parikh]

I really cannot thank you enough! I am curious as to how did you know this? This seems like something I would have never figured this out myself. Is it your experience and knowledge or is it there in some documentation?

[madhan ravi]

You by mistake named a variable tf , so you see how much of a pain it gives ya ;)

[Rik]

This is a fairly common mistake (it often happens with sum and image), so it is a reasonable guess given the error message.

You can check for things like this with the which command:

clc,clear
which tf -all
fprintf('\n   And now again with a variable in the workspace:\n\n')
tf=0;
which tf -all

[Niket Parikh]

Ah okay. Thank you madhan and Rik.