# HELP! can someone give me an example of composite function word problem

• Aug 11th 2012, 07:18 PM
jilian
HELP! can someone give me an example of composite function word problem
Pls i really need your help. i dont have any idea how to make a word problem for COMPOSITE FUNCTIONS. can you give a sample? THANKS GOD BLESS..
• Aug 12th 2012, 06:08 AM
HallsofIvy
Re: HELP! can someone give me an example of composite function word problem
Suppose the temperature recorded by a weather balloon is a function of height, T= f(h) (if you want a specific function, just put in any function you like for f), and that the height of the balloon is a function of time, h= g(t). Then the temperature, as a function of time, it the composite function, $\displaystyle T= f\circ g(t)= f(g(t))$.

Now, do you understand what that means? That is far more important than just giving an answer.
• Aug 12th 2012, 07:38 AM
Soroban
Re: HELP! can someone give me an example of composite function word problem
Hello, jilian!

Quote:

Make a word problem for composite functions. Can you give a sample?

I like HallsofIvy's example!

I think of composite functions as "machines" (number crunchers) in a row.

The first is a machine that converts time $\displaystyle (t)$ into height $\displaystyle (h).$

. . $\displaystyle t \;\to\;\boxed{\begin{array}{c}\text{Height} \\ h(t) \end{array}}\;\to\; h$

The second is a machine that converts height $\displaystyle (h)$ into temperature $\displaystyle (T).$

. . $\displaystyle h \;\to\;\boxed{\begin{array}{c}\text{Temp.} \\ T(h) \end{array}} \;\to\;T$

Placing the machines in sequence, we have:

. . $\displaystyle t \;\to\; \boxed{\begin{array}{c}\text{Height} \\ h(t) \end{array}} \;\to\;h\;\to\;\boxed{\begin{array}{c}\text{Temp.} \\ T(h) \end{array}}\;\to\;T$

If this were an "assrmbly line" in our "factory",
. . it would be practical and economical to have one machine to do the job.

. . $\displaystyle t \;\to\;\boxed{\begin{array}{c} T(h(t)) \end{array}} \;\to\;T$

This would convert time $\displaystyle (t)$ directly to temperature $\displaystyle (T)$.
• Aug 13th 2012, 02:41 PM
jilian
Re: HELP! can someone give me an example of composite function word problem
can you pls give an example math word problem for composite function?
• Aug 13th 2012, 03:34 PM
skeeter
Re: HELP! can someone give me an example of composite function word problem
Quote:

Originally Posted by jilian
can you pls give an example math word problem for composite function?

Let me google that for you