#1




Pure Maths
Always we have given the COMPOSITE FUNCTIONS in that format ie
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 f=?? g=?? ...... if somebody have any idea about this problem then please discuss..... (((AWA))) 
#2




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^22x9. (^ stands for power) We can arbitrarily say, f(x)=3x^22x. So g(y)=y9# 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 
#3




Composition functions
MR. ElementOf surprise!
u have written a thing which is mathematically incorrect. i.e. 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. 
The Following User Says Thank You to Ashher For This Useful Post:  
Ambreen Nasir (Saturday, October 10, 2009) 
Thread Tools  Search this Thread 


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
App Maths 2010  Dolokhov  Applied Mathematics  39  Wednesday, November 18, 2009 04:17 PM 
The Secrets of Water in Quran  Hurriah  Islam  0  Tuesday, November 13, 2007 11:45 PM 
Office  Maths 100%  Mr Ghayas  Humorous, Inspirational and General Stuff  0  Saturday, May 13, 2006 12:10 AM 