(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

f:]1,+∞[→]2,+∞[

x→ 2x/(x-1)

2. Relevant equations

Prove that f is injective and serjective.

3. The attempt at a solution

I already proved that it's injective by stating the injectivity law:

for every (a,b)ε]1,+∞[: f(a)=f(b) implies a=b

so: 2a/(a-1)=2b/(b-1) entails: 2ab-2b=2ab-2a entails -2b=-2a entails a=b

Can anyone please tell me how to prove that its serjective?

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# Polynomial Functions.

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