The graph of a square root function f is shown below. Find each of the following, if possible.
a. f(11)
b. f(-1)

Question

The graph of a square root function f is shown below. Find each of the following, if possible.
a.   f(11)
b.   f(-1)

e.mccormick · Answer

Know what it means when you put a number into a function?

$f(x)=\sqrt{x}$

$f(11)=\sqrt{11}$

$f(-1)=\sqrt{-1}$

anonymous · Answer

Thats what I thought but then I looked at the back of the book that gives the answers and it was 
a. 3
b. Undefined

e.mccormick · Answer

Yes.  You need to try and get the roots.  They seem to be doing it from a graph, so it is an estimate.

anonymous · Answer

Im so sorry but what do you mean they are doing it from a graph there is no graph given to me. Am I suppose to create it

e.mccormick · Answer

It says "The graph of a square root function f is shown below."

anonymous · Answer

Also how do you get the roots for f(11) to 3

e.mccormick · Answer

Well, here is the graph. When x is 11, what is y closest to? https://www.desmos.com/calculator/rbjpplht6a

anonymous · Answer

OHHH OK THANK YOU SO MUCH!

anonymous · Answer

That helps way more!

e.mccormick · Answer

Yah, they are taling about this: https://www.desmos.com/calculator/14sws5aoxx I added the x lines for 11 and -1.

anonymous · Answer

Thank you for clearing that up :)

e.mccormick · Answer

As you can see, -1 never touches the square root graph.  That is the undefined.  The other one they just want to know where it hits near.  The real root of 11 is closer to 3.32, but they are rounding to a whole number.

anonymous · Answer

yea which is why its undefined awesome!