What is 1 divided by 0? Is it infinity?

Source: http://en.wikipedia.org/wiki/Division_by_zero

Contrary to popular opinion, 1 divided by 0 is not infinity! Wikipedia states that “the expression has no meaning, as there is no number which, multiplied by 0, gives a (assuming a≠0), and so **division by zero is undefined**“.

## How to show that division by zero is undefined

The limit of 1/x as x approaches zero from the right is positive infinity.

However,

The limit of 1/x as x approaches zero from the left is negative infinity.

Since the left limit and right limit are different, the limit of 1/x as x approaches infinity does not exist!

Note: There are mathematical structures in which *a*/0 is defined for some *a* (see Riemann sphere, real projective line, and section 4 for examples); however, such structures cannot satisfy every ordinary rule of arithmetic (the field axioms).