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Example 4

If ε ≠ 0, the quotient

01_real_and_hyperreal_numbers-112.gif

is infinite.

We first note that the denominator 5ε4 + ε3 is not zero because it can be written as a product of nonzero factors,

4 + ε3 = ε · ε · ε · (5ε + 1).

When we cancel ε2 from the numerator and denominator we get

01_real_and_hyperreal_numbers-113.gif

We see in turn that:

ε2 - ε + 2 is finite but not infinitesimal,

2 + ε is infinitesimal,

01_real_and_hyperreal_numbers-114.gif is infinite.


Last Update: 2006-11-15