Confusing percale question...?

Which of the following could be an example of a function with a domain

[a, infinity)

and a range (-infinity, b]

where a 0 and b 0

Question

Confusing percale question...?

Which of the following could be an example of a function with a domain

[a, infinity)

and a range (-infinity, b]

where a > 0 and b > 0

misty1212 · Answer

HI!!

misty1212 · Answer

do you have to make one up?

misty1212 · Answer

we can do that if you like, but if you have choices then it will be easier to pick one

anonymous · Answer

Here are my choices http://i296.photobucket.com/albums/mm191/cholland2015/precal_zpsoptusrgt.png

anonymous · Answer

make a guess, i bet you are right!

misty1212 · Answer

lol one of those is the one i was going to suggest

misty1212 · Answer

you want the domain to be $[a,\infty)$ i as going to suggest something involving the square root of $x-a$

anonymous · Answer

I'm confused of where the infinity part comes in?

anonymous · Answer

that just means the domain is all numbers larger than $a$
don't fret about the $\infty$

anonymous · Answer

do what @misty1212  said, pick one with $\sqrt{x-a}$ since you cannot take the square root of a negative number that would mean $x-a\geq0$ so $x\geq a$

anonymous · Answer

Okay I see... I think. Thank you guys both for your help.

misty1212 · Answer

$$\color\magenta\heartsuit$$

anonymous · Answer

btw do you know why the range of $-\sqrt{x-a}+b$ is $(-\infty,b]$?