Re: Infinite Resistance
Originally posted by physis: Is it clearer now?
It?s perfectly clear now. That is because I found the web site that you have been using for your attempts to declare that division by zero can have meaning. As I suspected, you have taken it out of context. But I see the source of the confusion, and admit how easy it would be to miss the single most important detail contained within that web site?s descriptions.
In electrical engineering, we often must deal with ?complex numbers.? That set of numbers includes the ?real numbers? and numbers that involve taking the square root of negative one. We can plot information on a standard X ? Y graph in which the horizontal axis represents the real numbers (e.g., real power, or KW), and the vertical axis represents the complex numbers (e.g., reactive power, or KVAR). This type of X ? Y graph is said to have been laid out within the ?complex plane.? That phrase means that a flat sheet of paper (representing a plane) is used to model both real numbers and complex numbers. All of electrical analysis, including a formal analysis of the original question about Ohm?s Law for an open circuit, can be carried out within the limitations of the ?complex plane.? The rules for this ?complex plane? include the rule that division by zero is ?undefined.?
What you are describing, what you found on the Internet, is not the ?complex plane.? Rather, it is the ?
extended complex plane.? It was envisioned by a highly talented theoretical mathematician almost 400 years ago. The ?extended? part of his vision was allowing the plane to include the point at which two parallel lines intersect. That point, the so-called ?point at infinity,? does not literally exist (but for that matter, neither does the square root of negative one). But if you permit the theoretical ?pint at infinity? (side note: that was an accidental typo, but I think I?ll leave it there
) to exist, then you can conclude that ?complex infinity? is a number that can be reached by dividing 1 by zero. You can next establish a definition for ?1 / 0,? as you have pointed out. You cannot, however, take the next step of multiplying both sides of that definition by zero, and conclude that zero times ?complex infinity? equals one. The web site does state that clearly.
So I will be willing to grant your statement that "1 / 0" has a definition, and that that definition gives it a value of ?complex infinity,? if you will grant my assertions that (1) That definition only applies within the ?
extended complex plane,? and (2) The ?
extended complex plane? cannot be used in any electrical or electrical engineering context.