- #1

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How do you work out the domain and range of fg(x), do you work out what range of g(x) will fit the domain of f(x)?

I have no clue.

Thanks

- Thread starter CAH
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- #1

- 48

- 0

How do you work out the domain and range of fg(x), do you work out what range of g(x) will fit the domain of f(x)?

I have no clue.

Thanks

- #2

- 9

- 1

Hey CAH,

Sorry, but do you mean f(g(x)) or f(x) * g(x) ?

Sorry, but do you mean f(g(x)) or f(x) * g(x) ?

- #3

jbriggs444

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Based on the thread title, by fg(x) you mean f(g(x)). So you are trying to work out the domain and range for the composition of f with g.How do you work out the domain and range of fg(x), do you work out what range of g(x) will fit the domain of f(x)?

For the range, you would start with the range of the inner function -- g in this case. Figure out what outputs are possible from f when its inputs are in that range.

For the domain, you would start with the domain of the outer function -- f in this case. Figure out what inputs to g can produce outputs in that range.

- #4

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f(x)=3e^(2x) domain:(-infinity, +infinity)

g(x)=ln(4x) domain:(0, +infinity)

how would i go about finding the domain and range of f(g(x))?

(thanks for the reply)

- #5

HallsofIvy

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