Saturday, April 20, 2024
03:52 AM (GMT +5)

Go Back   CSS Forums > CSS Optional subjects > Group II > Pure Mathematics

Reply Share Thread: Submit Thread to Facebook Facebook     Submit Thread to Twitter Twitter     Submit Thread to Google+ Google+    
LinkBack Thread Tools Search this Thread
Old Tuesday, June 27, 2006
Junior Member
Join Date: Jun 2006
Location: Hyderabad Pak
Posts: 26
Thanks: 44
Thanked 14 Times in 10 Posts
abrowaqas is on a distinguished road
Default Pure Maths

Always we have given the COMPOSITE FUNCTIONS in that format i-e

f= something
g= something

and then we have to find "fog" and "gof" .....

but never in any book .. . composite functions are given then we have to find original functions...... i -e

fog= something
gof= something


...... if somebody have any idea about this problem then please discuss.....

Reply With Quote
Old Saturday, July 01, 2006
Join Date: May 2006
Posts: 54
Thanks: 0
Thanked 1 Time in 1 Post
elementofsurprize is on a distinguished road
Default One Approach

One approach can be this. We start with given: g(f(x))= something.

Now, we easily conclude: Dom(g(f(x))=Dom(f(x))
Range(g(f(x))=Range(g(y)) (assuming that g is defined over y)

Keeping this in mind we can arbitrarily make two functions out of the given g(f(x)) function so that all the variables are grouped in one function which we will call f(x) and the whole will be g(f(x)).

For example: Given: g(f(x))=3x^2-2x-9. (^ stands for power)
We can arbitrarily say, f(x)=3x^2-2x. So g(y)=y-9#

Now, if we are given some conditions regarding the functions f or g then we can't break g(f(x)) arbitratily. We have to break it in a way that the conditions for f and g are also satisfied.

I hope this helps you. If there are questions then I am interested too.
Smyler wyth nyfe undur the cloke
Reply With Quote
Old Saturday, July 22, 2006
Junior Member
Join Date: Jul 2006
Posts: 1
Thanks: 0
Thanked 1 Time in 1 Post
Ashher is on a distinguished road
Default Composition functions

MR. ElementOf surprise!
u have written a thing which is mathematically incorrect.
if g(f(x)) = something ...that does not imply that dom (g (f(x)) = dom (f(x)).
Consider the following counter example.....
Let f(x) = x^2. then Dom (g(f(x)) = postive real numbers and zero...however dom(f(x)) = All real numbers.
Reply With Quote
The Following User Says Thank You to Ashher For This Useful Post:
Ambreen Nasir (Saturday, October 10, 2009)

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
App Maths 2010 Dolokhov Applied Mathematics 39 Wednesday, November 18, 2009 05:17 PM
The Secrets of Water in Quran Hurriah Islam 0 Wednesday, November 14, 2007 12:45 AM
Office - Maths 100% Mr Ghayas Humorous, Inspirational and General Stuff 0 Saturday, May 13, 2006 12:10 AM

CSS Forum on Facebook Follow CSS Forum on Twitter

Disclaimer: All messages made available as part of this discussion group (including any bulletin boards and chat rooms) and any opinions, advice, statements or other information contained in any messages posted or transmitted by any third party are the responsibility of the author of that message and not of (unless is specifically identified as the author of the message). The fact that a particular message is posted on or transmitted using this web site does not mean that CSSForum has endorsed that message in any way or verified the accuracy, completeness or usefulness of any message. We encourage visitors to the forum to report any objectionable message in site feedback. This forum is not monitored 24/7.

Sponsors: ArgusVision   vBulletin, Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.