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OpenStudy (katecc379):

Composite functions?

OpenStudy (katecc379):

OpenStudy (katecc379):

@jim_thompson5910

jimthompson5910 (jim_thompson5910):

Recall that \[\Large (f \circ g)(x) = f(g(x))\]

OpenStudy (katecc379):

yes i know how to do that

jimthompson5910 (jim_thompson5910):

Start with f(x). Replace every x with g(x). \[\Large f(x) = \sqrt[3]{x+2}\] \[\Large f({\color{red}{x}}) = \sqrt[3]{{\color{red}{x}}+2}\] \[\Large f({\color{red}{g(x)}}) = \sqrt[3]{{\color{red}{g(x)}}+2}\]

jimthompson5910 (jim_thompson5910):

so we end up with `g(x)+2` and we want that to be equal to `x+3` so set the two expressions equal to one another and isolate g(x)

jimthompson5910 (jim_thompson5910):

g(x) + 2 = x+3 g(x) = ????

OpenStudy (katecc379):

x+1?

jimthompson5910 (jim_thompson5910):

yep

OpenStudy (katecc379):

ok can u help with one more?

jimthompson5910 (jim_thompson5910):

sure

OpenStudy (katecc379):

howve you been its been forever haha

OpenStudy (katecc379):

jimthompson5910 (jim_thompson5910):

I'm doing well. How about you?

jimthompson5910 (jim_thompson5910):

the same idea will apply here but now we have 3 functions this time

OpenStudy (katecc379):

pretty good busy i work 12 hours everyday and take 7 classes online so im pretty stressed

jimthompson5910 (jim_thompson5910):

the inner most function is h(x) replace every x in h(x) with 4. Then evaluate to get what?

OpenStudy (katecc379):

sq rt of 4?

OpenStudy (katecc379):

2?

jimthompson5910 (jim_thompson5910):

`i work 12 hours everyday and take 7 classes online` that sounds like an impossible task, but somehow you're making it work

jimthompson5910 (jim_thompson5910):

yes the square root of 4 is 2

jimthompson5910 (jim_thompson5910):

now you'll plug that into g(x)

OpenStudy (katecc379):

yeah somehow couldnt tell you how haha but 7?

jimthompson5910 (jim_thompson5910):

plug x = 2 into g(x) to get ???

jimthompson5910 (jim_thompson5910):

yep 7

OpenStudy (katecc379):

okay then what

jimthompson5910 (jim_thompson5910):

then that result is fed into f(x)

jimthompson5910 (jim_thompson5910):

it's like a chain reaction

OpenStudy (katecc379):

so 28

jimthompson5910 (jim_thompson5910):

yep

OpenStudy (katecc379):

awwesome is this correct btw?

jimthompson5910 (jim_thompson5910):

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