You are Here: Home >< Maths

# Core 3

Announcements Posted on
Why bother with a post grad course - waste of time? 17-10-2016
1. (Original post by Ayaz789)
Complete the square on what? On f(x)?
Sketch the graph of fg(x). What is the domain of this function? Hence, what is it's corresponding range?
2. (Original post by Zacken)
Sketch the graph of fg(x). What is the domain of this function? Hence, what is it's corresponding range?
Im going to have to do all that for 1 mark? Well not even 1 mark , idek if we lose a mark
3. (Original post by Ayaz789)
Im going to have to do all that for 1 mark? Well not even 1 mark , idek if we lose a mark
Having properly read the question, where do you get -16 from? The range is [-25, ifinity).
4. (Original post by Zacken)
Having properly read the question, where do you get -16 from? The range is [-25, ifinity).
(-16, infinity) the range of fg?
5. (Original post by Ayaz789)
(-16, infinity) the range of fg?
Yeah, how do you get that?
6. (Original post by Zacken)
Yeah, how do you get that?
Because i got the domain of g and put into the function of G then put the range of g into the function of f(X)
7. (Original post by Ayaz789)
Because i got the domain of g and put into the function of G then put the range of g into the function of f(X)
Yeah, and you get that the minimum value of f(x) is clearly -25 which occurs when g(x) = 0 which occurs within the domain of g(x).
8. (Original post by Zacken)
Yeah, and you get that the minimum value of f(x) is clearly -25 which occurs when g(x) = 0 which occurs within the domain of g(x).
Okay nw , ill just do what i can in the exam!
9. (Original post by IrrationalRoot)
[a,b] means all the real numbers between a and b including a and b.
(a,b) means all the real numbers between a and b excluding a and b.
[a,b) means all the real numbers between a and b including a and excluding b.
(a,b] means all the real numbers between a and b excluding a and including b.
Of course, if a or b are ±infinity, then there will be a round bracket because obviously infinity is not included.

That's about as comprehensive of an explanation you can get.
Thanks for trying to help me , somethings just don't go into me , this is 1 of them , sorry!
10. (Original post by Ayaz789)
Thanks for trying to help me , somethings just don't go into me , this is 1 of them , sorry!
But it's so simple...
11. (Original post by IrrationalRoot)
But it's so simple...
I do further maths too which makes it worse :O and im going to study maths at Uni which makes me sounds awful at maths!:/
12. (Original post by Ayaz789)
I do further maths too which makes it worse :O and im going to study maths at Uni which makes me sounds awful at maths!:/
Tbf this is nothing about maths ability, so dw in that respect.
But it is common sense lol.
13. (Original post by IrrationalRoot)
Tbf this is nothing about maths ability, so dw in that respect.
But it is common sense lol.
Yeahh,i understand it a bit now, that if its square its including the number , if its a curved then its between that number and the the other bracket , well you tried to help!
14. (Original post by Ayaz789)
Yeahh,i understand it a bit now, that if its square its including the number , if its a curved then its between that number and the the other bracket , well you tried to help!
There we go!
15. (Original post by IrrationalRoot)
There we go!
Is that right?
16. (Original post by Ayaz789)
Is that right?
You are asking 'how do I know what the 'range of values is going to be', as opposed to the issue of notation - i.e what [ ] and ( ) etc mean.

You just work it out from the question or whatever's being asked. Eg if I asked you what the domain of lnx is, then you know that since lnx is undefined for x less than or equal to 0, you get that x>0 so the domain is (0,infinity]
17. (Original post by SeanFM)
You are asking 'how do I know what the 'range of values is going to be', as opposed to the issue of notation - i.e what [ ] and ( ) etc mean.

You just work it out from the question or whatever's being asked. Eg if I asked you what the domain of lnx is, then you know that since lnx is undefined for x less than or equal to 0, you get that x>0 so the domain is (0,infinity]
Wont it be (0, infinity)
18. (Original post by Ayaz789)
Wont it be (0, infinity)
that is a can of worms for me, I'm afraid
19. (Original post by SeanFM)
that is a can of worms for me, I'm afraid
Haha am i right?
20. (Original post by Ayaz789)
Haha am i right?
As long as you see the point I am trying to illustrate. Eg domain (for real values of x) of = ..

## 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: June 4, 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

### How does exam reform affect you?

From GCSE to A level, it's all changing

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