It is currently 21 Nov 2018, 02:09
My Tests

Close

GMAT 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

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Graph of the function f in the xy-plane

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jun 2014
Posts: 4722
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 91

Kudos [?]: 1630 [0], given: 390

CAT Tests
Graph of the function f in the xy-plane [#permalink] New post 14 Dec 2015, 05:54
Expert's post
00:00

Question Stats:

85% (00:40) correct 14% (00:55) wrong based on 14 sessions
Image

The figure above shows the graph of the function f in the xy-plane. What is the value of \(f(f(-1))\) ?

A. −2
B. −1
C. 0
D. 1
E. 2


[Reveal] Spoiler: attachment
Attachment:
Quant.jpg
Quant.jpg [ 10.9 KiB | Viewed 6391 times ]


Practice Questions
Question: 7
Page: 152
Difficulty: medium
[Reveal] Spoiler: OA

_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

1 KUDOS received
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jun 2014
Posts: 4722
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 91

Kudos [?]: 1630 [1] , given: 390

CAT Tests
Re: Graph of the function f in the xy-plane [#permalink] New post 14 Dec 2015, 05:59
1
This post received
KUDOS
Expert's post
Solution

Here we have a functions whose values are defined Graphically.

We need to compute the value of \(f(f(-1))\). To do so we need to find the value of \(f(-1)\) first. Now looking up the value from the graph we see that \(f(-1)= 2\).

Hence the problem is reduced to finding the value of \(f(2)\). Again from the graph we see that \(f(2) = 1\).

Thus \(f(f(-1))=1\).
_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

Intern
Intern
Joined: 12 Jul 2017
Posts: 9
Followers: 0

Kudos [?]: 4 [0], given: 2

Re: Graph of the function f in the xy-plane [#permalink] New post 24 Jul 2017, 07:35
Could anyone explain more in detail why the solution is D. I am lost.
Intern
Intern
Joined: 17 Jul 2017
Posts: 15
Followers: 0

Kudos [?]: 7 [0], given: 13

Re: Graph of the function f in the xy-plane [#permalink] New post 25 Jul 2017, 23:57
So my understanding is - in case we have these kind of functions say f(f(f(f(-2) (say based on above graph) we keep substituting the innermost value of f? Please do let me know. thank you!
1 KUDOS received
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jun 2014
Posts: 4722
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 91

Kudos [?]: 1630 [1] , given: 390

CAT Tests
Re: Graph of the function f in the xy-plane [#permalink] New post 26 Jul 2017, 06:24
1
This post received
KUDOS
Expert's post
TUTTIAM52 wrote:
Could anyone explain more in detail why the solution is D. I am lost.


We evaluate the brackets first. So we find the value of \(f(-1)\) from the graph \(f(-1)=2\). So putting the value of \(f(-1)\) in \(f(f(-1))=f(2)\).

Now we look up tha value of \(f(2)\) from the graph

nancyjose wrote:
So my understanding is - in case we have these kind of functions say f(f(f(f(-2) (say based on above graph) we keep substituting the innermost value of f? Please do let me know. thank you!



Yes you are right!
_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

GRE Instructor
User avatar
Joined: 10 Apr 2015
Posts: 1188
Followers: 44

Kudos [?]: 1059 [0], given: 6

CAT Tests
Re: Graph of the function f in the xy-plane [#permalink] New post 15 Oct 2017, 19:00
Expert's post
sandy wrote:
Image

The figure above shows the graph of the function f in the xy-plane. What is the value of \(f(f(-1))\) ?

A. −2
B. −1
C. 0
D. 1
E. 2


[Reveal] Spoiler: attachment
Attachment:
Quant.jpg



Many people struggle with function notation.
However, it's really just the same as the "y = some expression with x" notation you've seen before (e.g., y = 3x + 1)

So, for example, asking for the value of f(-1) is the same as asking "What the value of y is when x = -1?"

When we look at the given graph we see that the point (-1, 2) lies ON the graph.
So, we can say "when x = -1, y = 2"

This is exactly the same as saying f(-1) = 2

Now that f(f(-1)) = f(2), what is the value of f(2)?
This is the same as asking "What's the value of y when x = 2?"

When we look at the given graph we see that the point (2, 1) lies ON the graph.
So, we can say "when x = 2, y = 1"

In other words, f(2) = 1

So, f(f(-1)) = f(2) = 1

Answer:
[Reveal] Spoiler:
D


RELATED VIDEO

_________________

Brent Hanneson – Creator of greenlighttestprep.com
Image
Sign up for our free GRE Question of the Day emails

Re: Graph of the function f in the xy-plane   [#permalink] 15 Oct 2017, 19:00
Display posts from previous: Sort by

Graph of the function f in the xy-plane

  Question banks Downloads My Bookmarks Reviews Important topics  


GRE Prep Club Forum Home| About| Terms and Conditions and Privacy Policy| GRE Prep Club Rules| Contact

Powered by phpBB © phpBB Group

Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.