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

find the domain and image of f such that

f(x) = {(x,y) [tex] \in R \times R \vert x = \sqrt{y+3} [/tex]

and domain and image of g such that

g = {[tex] (\alpha,\beta) \vert \alpha is a person, \beta is a person, \alpha is the father of \beta [/tex]

2. Relevant equations

the domain and image are what would be expected of domain and image. No unstandard definitions.

3. The attempt at a solution

I think the answers in the back of the book are wrong. I will state my answers, the ones in the book have the opposite for domain and range (although it is a copyright 2009 book). It is also possible that I am wrong.

okay for f, the function can be rewritten by substituing [tex] \sqrt{y+3} [/tex] for x.Then ,

f = {[tex] (\sqrt{y+3},y) \vert y \in R [/tex]. This means that the domain will consist of values that are bigger or equal to -3. So, [tex] dom f = \{x \vert x \in R , x \geq -3 \} [/tex]. And following that, the image of f is the set of values that are greater than or equal to zero. [tex] im f = \{y \vert y \in R, y \geq 0 \}[/tex].

For the second one. The domain is all people who are fathers, and the image is all people.(assuming that any person has a father where father denotes only a biological relationship).

Any suggestions?

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# Homework Help: Discrete math textbook problem

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