What's 1/0? Infinity, right? We said above that we can't divide by zero. But, can't we divide by zero, if we're careful? Let's look at 1/0, more closely. In Calculus, we deal with problems like this by using limits. In other words, we don't look at 1/0, we look at 1/x (the graph of y = 1/x is shown on the left) when x gets close to zero. Well, when x gets close to zero, 1/x gets very large without bounds, it is infinity. Not so fast, x also gets close to zero on the negative side. Then 1/x becomes a very large negative number, without bounds, it is negative infinity. So, the answer to the question, &quot;What is 1/0?&quot; is &quot;plus-or-minus infinity.&quot; Kind of a wild answer, isn't it? It is not exactly simple.<br />
So, an apparently simple situation like 1/0 blows up in our faces. That's another good reason for not allowing division by zero.