inverse number (original) (raw)

The inverse number or reciprocal number of a non-zero real or complex number a may be denoted by a-1, and it the quotient 1a (so, it is really the -1th power of a).

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  Two numbers are inverse numbers of each other if and only if their product is equal to 1 (cf. opposite inverses).
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  If a (≠0) is given in a quotient form bc, then its inverse number is simply

  (bc)-1=cb.

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  Forming the inverse number is also a multiplicative function, i.e.

  (b⁢c)-1=b-1⁢c-1
  (to be more precise, it is an automorphism of the multiplicative group of ℝ resp. ℂ).