Are setWidth(null) and setSizeUndefined() the same?

General
1

Hi,
-Sorry if it has been asked before-
I want to know if the methods
setWidth(null)
 and
setSizeUndefined()
 do the same.
(Apparently, yes)

Thanks

2 
setSizeUndefined();

is a shortcut for

setWidth(null);
setHeight(null);
3

Thanks!