I am using Matlab R2010b. I want to make a reference line at coordinates x=0 and y=0. I used to do that in Matlab 2009 but now can't do that. It gives me an error message " Undefined function or method 'refline' for input arguments of type 'double'". I changed the data type to single but I am still getting the same message. Could you please tell me hoe I can fix it?