Course:MATH110/Archive/2010-2011/003/Math Forum/Webwork Week 8

Problem 8

I am having difficulty getting this one:

$h(x)={\sqrt {\frac {9x}{x^{2}-361}}}$

Given that -19 and 19 for x would cause the denominator to equal 0, I thought this was the answer:

(-infinity,-19)U(-19,19)U(19,infinity)

but that is incorrect. Maybe I am thinking about this in the wrong way. Anyways, I am stuck on this one and would appreciate a hint. 20:05, 28 October 2010 (UTC)

I also have the same values as you, and what I have seen is that -19 and 19 don't work, but numbers between 1 through 18 don't work either because the bottom will be a negative number meaning the overall thing will be negative. So I have tried (-infinity, -19)U(-19,0]U(19,infinity) but that is also incorrect. I think it might be something about me excluding numbers between 1 through 18. I still haven't found the answer, but if that helps you find it. --JoseTorresTorija

Hey Steffany

So you were given that -19 and 19 would make the denominator equal to 0, recall that we could not have any negative value in the square root as it would be undefined.

Therefore I got (-19,0]U(19,infinity), try this and I think it should work. --Narissarasu

Q6

Was Question 6 removed from the Webwork?

I think so, I realized one of the questions was missing.

Because it had a bug -- DavidKohler

Problem 4

Can anyone help me out with question 4?

Problem 4 is tricky. Here is my hint for solving it. Think of each job as a different option. So you have two options which can be represented by two different formulas (I will let you work out the formulas). The key to answering this is the wording "at least as good." Another way of saying at least as good is saying "equal." Once you have your two formulas, think of what you do with the formulas to solve this...