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# C3 functions pt 2 watch

1. http://www.examsolutions.net/a-level...e/paper.php#Q7

How can i work out f(x) ???? for part d of question 7?
2. (Original post by bigdonger;[url="tel:66437494")
66437494[/url]]http://www.examsolutions.net/a-level...e/paper.php#Q7

How can i work out f(x) ???? for part d of question 7?
In your g(X), replace the X with f(X) then make it equal to 16 and solve for f(x)

Then consider the two sections of f(x) and see which X values give you what you found
3. It tells you all the information at the top. If you look at the graph of f you should see that it involves the modulus function.
4. (Original post by RDKGames)
In your g(X), replace the X with f(X) then make it equal to 16 and solve for f(x)

Then consider the two sections of f(x) and see which X values give you what you found
i know this is the way to do it but i don't know how :/
(Original post by B_9710)
It tells you all the information at the top. If you look at the graph of f you should see that it involves the modulus function.
so the function of that graph is f(x)=|x|-2 ??? but how am i supposed to sub that into g(x) and is doesn't tell me it's a modulus...
5. (Original post by bigdonger)
i know this is the way to do it but i don't know how :/

so the function of that graph is f(x)=|x|-2 ??? but how am i supposed to sub that into g(x) and is doesn't tell me it's a modulus...
|x-2| is not the equation. The gradient is completely different for x<2 and x>2. It's a piecewise function.

6. This is the function for the domain specified in the question. (I was wrong about the modulus function as I just glanced over the question).
If you're not sure find what value of x needs to be put into g to give 16. Then find what values of x you need to put into f so that f gives the value you need. Hope this makes sense may not have explained it too well.
7. (Original post by B_9710)
|x-2| is not the equation. The gradient is completely different for x<2 and x>2. It's a piecewise function.
(Original post by B_9710)

This is the function for the domain specified in the question. (I was wrong about the modulus function as I just glanced over the question).
If you're not sure find what value of x needs to be put into g to give 16. Then find what values of x you need to put into f so that f gives the value you need. Hope this makes sense may not have explained it too well.
OOOOHHHHHH!!!! That looks very familiar.
I understand how to work things out from that big thing there. Never knew you had to construct one of those :O
thanks

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Updated: July 15, 2016
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