##
O7: Positive numbers have positive reciprocals.

*"*If *a*>0 then 1/*a*>0.*"* *(see ita-2-2-13-pg20)*

*"*In fact *a*·(1/*a*) = 1>0, [and by O5 both factors in the product must be positive since one factor and the product are positive].*"* *(see ita-2-2-13-pg20)*

Recall that division, and hence 1/*a*, was defined in F4. Also, 1/*a* is called the *reciprocal* of *a*.

Converted [ in part ] by *Mathematica*
December 4, 2007