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C3 graph question

1479904360416-2099726512.jpg for question 8, I don't get how you can spot the fact that the inverse function is negative . From my working , the inverse function is a positive root but somehow at the end u have to change it to negative since the domain is x >-3 but I don't get why...

Thanks
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Pawini
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Original post by coconut64
1479904360416-2099726512.jpg for question 8, I don't get how you can spot the fact that the inverse function is negative . From my working , the inverse function is a positive root but somehow at the end u have to change it to negative since the domain is x >-3 but I don't get why...

Thanks



The inverse function is root(x+3/2)
The range of the first graph is y>-3 so for the inverse you just switch the range to domain.
IMG_1838.PNG
Here's a picture of the graphs if it helps.
Original post by coconut64
1479904360416-2099726512.jpg for question 8, I don't get how you can spot the fact that the inverse function is negative . From my working , the inverse function is a positive root but somehow at the end u have to change it to negative since the domain is x >-3 but I don't get why...

Thanks


To determine f^-1(x) follow the following steps:
1) Replace f(x) with y.
2) Make x the subject.
3) swap x with y.
4) Replace y with f^-1(x)

The domain of the inverse function is the range of the function. Therefore it must be greater than -3 because when you put 0 into f(x) you get -3.
Thank me later.
My explanation is a bit better still. Get in the bin Pawini.

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