Answer with proof required. 1? It's undefined. Because the reason that any number multiplied by infinity is also infinity is because there was something there to start with. Discussions. Any number multiplied by \$0\$ is \$0\$. Even if infinity is really big, if there are zero amounts of infinity, that would make zero. It may also have to do with conflicting definitions: generally speaking, for some number n, n * 0 = 0, and n * infinity = infinity. Tags: math infinity divide zero 0 ohm s law ideal voltage source. Any number multiply by infinity is infinity or indeterminate. So long as the number system is a field, anything multiplied by \$0\$ will necessarily give \$0\$, even if the "anything" is an infinite number. Infinity minus infinity, due to the nature of infinity, can be zero, infinity, or minus infinity (I - I = -I, 0, I). Does infinity divided by zero theoretically equal any number other than 0 or infinity? 0*infinity =0 (zero squared really is zero; this simplification is legitimate) OK, that's one of the values you accept so we agree. I heard something about ohm's law applied to a circuit with an ideal voltage source (which is only theoretically possible) and having the terminals shorted out and at 0 ohms, resulting in the current going up to infinity? Why isn't zero multiplied by infinity equal to zero? The answer is 0. Guess not. Division by zero (and the equivalent multiplication by infinity… This is equivalent to writing zero an infinite number of times and then adding them together. I read that it this expression is called an "indeterminate form." 0 * infinity What is up? \$0\$ multiplied by infinity is the question. It is undefined. What is infinity multiplied by zero? So what is infinity * 0? This is an amusing game but contributes little to mathematics so those in charge simply banned it. How about 1infinity? If there is absolutely nothing you can multiply it by anything you like and still get zero. Infinity multiplied by zero results in zero.