I'm not really sure what it is asking me

lim -->5+$\displaystyle \sqrt{5-x}=?$

The provided answers are

a.) not real

b.) 0

c.) 1

d.) none of these

I feel like it is 0. Since 5-5 is 0. Could someone help me here?

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- Feb 19th 2008, 06:08 AMXIII13ThirteenLimits question (multiple choice)
I'm not really sure what it is asking me

lim -->5+$\displaystyle \sqrt{5-x}=?$

The provided answers are

a.) not real

b.) 0

c.) 1

d.) none of these

I feel like it is 0. Since 5-5 is 0. Could someone help me here? - Feb 19th 2008, 06:17 AMihmth
Is that all the informtion? I think it should give the value of x.

- Feb 19th 2008, 06:21 AMXIII13Thirteen
That might be what is confusing me it does have $\displaystyle lim x---->5+$. The teacher said that is X from the positive side

- Feb 19th 2008, 06:28 AMihmth
so maybe the function is $\displaystyle \sqrt{5-x}$ and its asking for the value of the function as it approaches to 5. if that's the case, the answer will be 0.

- Feb 19th 2008, 07:42 AMihmth
wait, im not really sure about this. there is also a possibility that the answer will not be 0, because if you will graph it:

Attachment 5131 - Feb 19th 2008, 10:36 AMXIII13Thirteen
That is a good point. I might just ask the teacher to clarify. I appreciate your help

- Feb 19th 2008, 11:02 AMPlato
- Feb 19th 2008, 11:03 AMwingless
$\displaystyle \lim_{x\to 5^{+}} \sqrt{5-x}$

Graph:

http://img98.imageshack.us/img98/2015/graphwq6.gif

It's a one sided limit. What does it approach while x goes to 5 from left? It doesn't approach anywhere because f(x) isn't defined for $\displaystyle x>0$ ! - Feb 19th 2008, 11:42 AMxifentoozlerix
The limit does not exist. By definition, the limit

**must**be a**real**number. I agree with Plato in that the correct choice must be (d). To say "such and such limit is not real" would be a very ambiguous statement. Is it implying that the limit exists, but is not a real number?(Worried). Or, is it implying that "not real" is the same thing as "does not exist"? Either way, it is still worth clarifying with your teacher what he/she thinks is the correct answer so you don't get points taken off of an exam for being "too correct". It comes down to semantics.