Find a value(s) for x that would make this function undefined?

strahan

New member
Joined
Mar 24, 2019
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2
I have no idea how to do this question, it would be great if someone could give me some pointers. It says to put it into a graphing calculator and "find the values for x that would make this function undefined". the equation is: g(x) = √x-4 . I have attached an image that shows the exact question on the sheet.

11506

Thanks!
 

MarkFL

Super Moderator
Staff member
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Nov 24, 2012
Messages
1,733
Hello, and welcome to FMH! :)

If you graph that function, you should see something like this:

fmh_0025.png

Based on this, what values of \(x\) would you say are outside of the domain?

To find this algebraically, we must observe that the radicand (expression under the radical) cannot be negative, and so to find what values of \(x\) do make that radicand negative, we could write:

\(\displaystyle x-4<0\)

What happens if you add 4 to both sides of the inequality?
 

strahan

New member
Joined
Mar 24, 2019
Messages
2
Hello, and welcome to FMH! :)

If you graph that function, you should see something like this:

View attachment 11507

Based on this, what values of \(x\) would you say are outside of the domain?

To find this algebraically, we must observe that the radicand (expression under the radical) cannot be negative, and so to find what values of \(x\) do make that radicand negative, we could write:

\(\displaystyle x-4<0\)

What happens if you add 4 to both sides of the inequality?
Thank you heaps for your help!
 

JeffM

Elite Member
Joined
Sep 14, 2012
Messages
3,434
With respect to the second question, can you see any values of x for which b(x) is NOT defined?

Do you see what to do next?
 
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