Analysis of information sources in references of the Wikipedia article "Comparison of HP graphing calculators" in English language version.
The original hp 38g only had the function INVERSE(…) and the -1 operator was added for convenience sake in the hp 39g, released in 2000. To do this the creators had to borrow one of the existing unused characters, the 3 character, and convert it into the -1 operator. However, they forgot to change it in the CHARS view and this error has never been fixed in any of the successive models!
The original hp 38g only had the function INVERSE(…) and the -1 operator was added for convenience sake in the hp 39g, released in 2000. To do this the creators had to borrow one of the existing unused characters, the 3 character, and convert it into the -1 operator. However, they forgot to change it in the CHARS view and this error has never been fixed in any of the successive models!
