You are Here: Home >< Maths

# C3 functions pt 2

Announcements Posted on
Four hours left to win £100 of Amazon vouchers!! Don't miss out! Take our short survey to enter 24-10-2016
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

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: July 15, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### Who is getting a uni offer this half term?

Find out which unis are hot off the mark here

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read here first

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams