GRE Prep Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Assume the function f(x) is defined as follows: f(x) =
[#permalink]
22 Jul 2019, 02:51
22 Jul 2019, 02:51
1
Expert Reply
5
Bookmarks
00:00
Question Stats:
59% (00:52) correct
40% (01:03) wrong based on 135 sessions
Hide Show timer Statistics
Assume the function f(x) is defined as follows: \(f(x) = (x – 4)^2 + \sqrt{x+3} + \frac{5}{x+2}\). For which of the following values of x is f(x) defined?
Indicate all such values.
A. –5
B. –4
C. –3
D. –2
E. –1
Indicate all such values.
A. –5
B. –4
C. –3
D. –2
E. –1
Re: Assume the function f(x) is defined as follows: f(x) =
[#permalink]
24 Jul 2019, 10:24
24 Jul 2019, 10:24
1
here we need to consider two constraints.
We can't have square root of negative numbers. So, x+3 >=0 or, x>= -3
We can't have denominator 0. So x+2 not equal i.e. x not equal -2
From first constraint, we get values -3, -2, -1. But from the second constraint, we have to exclude -2. Thus, -3 and -1 are our answers.
We can't have square root of negative numbers. So, x+3 >=0 or, x>= -3
We can't have denominator 0. So x+2 not equal i.e. x not equal -2
From first constraint, we get values -3, -2, -1. But from the second constraint, we have to exclude -2. Thus, -3 and -1 are our answers.
Re: Assume the function f(x) is defined as follows: f(x) =
[#permalink]
30 May 2020, 11:56
30 May 2020, 11:56
2
What does it mean to be undefined?
There are a lot of situations that are undefined, but two of the most common in GRE-level math are 1) taking the square root of a negative number and 2) dividing by zero.
For each of the items being added up, you only have to look at two: sqrt(x+3) and 5/(x+2)
For the first, x has to be greater than or equal to -3 in order to not be a negative number under the square root sign. Eliminate A and B.
For the second, x cannot be equal to -2 so that you're not dividing by zero. Eliminate D.
For the values of X for answers C and E, you've got a defined equation. Those are the answers!
There are a lot of situations that are undefined, but two of the most common in GRE-level math are 1) taking the square root of a negative number and 2) dividing by zero.
For each of the items being added up, you only have to look at two: sqrt(x+3) and 5/(x+2)
For the first, x has to be greater than or equal to -3 in order to not be a negative number under the square root sign. Eliminate A and B.
For the second, x cannot be equal to -2 so that you're not dividing by zero. Eliminate D.
For the values of X for answers C and E, you've got a defined equation. Those are the answers!
