# function composition

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• Mar 27th 2012, 05:24 PM
noork85
function composition
i am utterly confused about this.

question says: find two functions f and g so that h(x)=2(x-9)^3-(x-9)^2+4

i dont know the first step id take to go about this problem, any help would be appreciated. this was a question on my test and i got it wrong, and it was a full 6pt deduction. :(

thanks!
• Mar 27th 2012, 05:31 PM
skeeter
Re: function composition
Quote:

Originally Posted by noork85
i am utterly confused about this.

question says: find two functions f and g so that h(x)=2(x-9)^3-(x-9)^2+4

i dont know the first step id take to go about this problem, any help would be appreciated. this was a question on my test and i got it wrong, and it was a full 6pt deduction. :(

thanks!

you just need to notice one function "inside" another ...

\$\displaystyle g(x) = x-9\$

\$\displaystyle f(x) = 2x^3 - x^2 + 4\$

\$\displaystyle h(x) = f[g(x)]\$
• Mar 27th 2012, 05:33 PM
noork85
Re: function composition
ahh...i see. i failed to notice that it says "composition"

thank u very much!