#1
ok so i just joined this pre-calc class Friday and im kind of lost. im getting some of it right but im never sure with this so of. Were doing composite functions. Here’s the problem.

Find (FoG) and (GoF)
F (x)= x^3
G (x)= x+1

Here’s how i think u solve (FoG)
X (x+1)^3 with equal’s x4+3x3+3x2+x
again not sure if right. plz help
Last edited by pawnshop_1919 at Sep 9, 2007,
#2
FoG means plug in the function G wherever you see x in F.

So FoG would be 3(x+1) = 3x + 3

and GoF means plug in the function F wherever you see x in G.

So GoF would be (3x) + 1 = 3x + 1
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#6
Haha. I have the same class, and we just learned that last week.

(FoG) would be (x+1)^3
(GoF) would be (x^3)+1.

I'm pretty sure.
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#7
Quote by pawnshop_1919
where did u get the 3. its to the x to the 3rd power.


Then you f*cking say x^3. Not x3.
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#10
Then FoG would be (x+1)^3 = x^3 + 3x^2 + 3x + 1

and GoF would be x^3 + 1.
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#11
Quote by RedMoonMan
1st of all that isnt even precalc second of all that is really simple


It is something you learn in precalc, dumbass. Have you looked at a precalc textbook recently?
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#12
if F(x)=x^3, then:
FoG=(x+1)^3
=(x+1)(x^2+2x+1)
=x^3+2x^2+x+x^2+2x+1
=X^3+3x^3+3x+1
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#13
Quote by darkstar2466
Then FoG would be (x+1)^3 = x^3 + 3x^2 + 3x + 1

and GoF would be x^3 + 1.


Correct.
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#15
In Calculus, you will apply this chain rule to do differentiation.
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#16
ok thx. i dont know why i put the X on outside of the equation
thx again darkstar2466 and everyone else. even the jackasses