# Why is there only one type of imaginary number? [duplicate]

We've defined the square root of -1 as an imaginary number i (or j, if you're a physicist).

Is there any reason why we can't/haven't made other systems of imaginary numbers for other "impossible" operations, like log base 1 or dividing by zero?

• Note the $\log_1$ question is kind of the same as the other question by the change of base formula. – jgon Apr 28 '15 at 22:05
• – Chappers Apr 28 '15 at 22:08
• I find most physicists I encounter use i, its nearly every electrical engineer I meet that typically uses j. Not that we aren'r aware of the use of j...we would mix it up with generalized currents which we normally use j for – Triatticus Apr 28 '15 at 22:15
• It is, imho, mostly a practical question. You can define anything you like and we do all the time (e.g we write "Let x be..."). Something gets a name or a letter if it is useful. Pi is useful, Euler's e is useful and so are complex numbers. If tomorrow you'll find a constant or a concept that is useful or practical it will get a life of its own and maybe even its own letter.... – DannyDan Apr 28 '15 at 22:21