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# Official Edexcel C3 Discussion Thread watch

http://www.wolframalpha.com/input/?i...%5E2%29%29%2B3

judge for yourself if it is fg(x) >=3
I understand your point and the range of this function appears to be x>=3

However as this range is for the composite function fg(x) you have to consider the domains of each singular function f(x) and g(x) before they have been composed into a single function. As the domain of g(x)>1 then this still applies when finding the range of fg(x) and therefore it has to be x>3 as we cannot input the value -1 which gives out x=3.

I did the test myself and put x>=3 realising afterwards that I did not consider the domain of g(x). In all of the past papers I have seen you have to consider this so it looks like the answer is going to be x>3 I am afraid.

I fear the debate will still rage on though
2. (Original post by semolina pilchard)
I understand your point and the range of this function appears to be x>=3

However as this range is for the composite function fg(x) you have to consider the domains of each singular function f(x) and g(x) before they have been composed into a single function. As the domain of g(x)>1 then this still applies when finding the range of fg(x) and therefore it has to be x>3 as we cannot input the value -1 which gives out x=3.

I did the test myself and put x>=3 realising afterwards that I did not consider the domain of g(x). In all of the past papers I have seen you have to consider this so it looks like the answer is going to be x>3 I am afraid.

I fear the debate will still rage on though
omg I was confused as well, but then I thought they just asked about the range of (x-1)^2 + 3, not relating to f/g(x) so I put down >=3
3. (Original post by crazedmonkey09)
you reckon i will lose a mark for leaving it as 4/(3x+3)(3x+1)
no you will not ....full marks there!!
4. please guys STOP GIVING EXPLANATIONS FOR Q8 AND THE RANGE QUESTION!!!!

i am sick and tired of different people asking for the answers, then others explaining, then again counter-arguments.

Arsey has given the explanation which is full and final.

just scroll back a few pages and read the posts instead of asking the same questions again and again
5. (Original post by vivienuytlop)
last year I did c2 . One question got 4 answers but I got only 2, still have 100%
In this c3 exam i got only 3 answers for the cot2x question by stupid mistake T___T Can i still have 100% ?
You got 100 UMS, right? That could be 73-75/75. So yes, you probably can.
6. The following graph shows all the marks for an A grade over a number of years.See how the graph is rising.
Attached Files
7. c3 grade.doc (23.5 KB, 358 views)
8. What goes up, must come down.
9. When I saw the grade boundary for June '09, my jaw dropped..

67/75 is unbelievably high for just an A.

This year's paper was hard though, don't you think?

I'd expect it to drop
10. (Original post by methyl benzene)
See how the graph is rising.
well it isn't always rising, is it
11. im sooooo screwed..
12. It was a hard paper, the grade boundaries have to be lowered!! It would be very unfair if they didn't.
13. i hope it is 58-57 for an A, so that for 90UMS it will be 65-64
14. (Original post by goldsilvy)
What goes up, must come down.
Exam questions defy the laws of gravity so that proverb doesn't belong to C3!
15. Grade boundaries are based on the past year stastics along with previous year statistics and not only the specific exam taken as said in the Edexcel Training workshop once
16. (Original post by zomgleh)
quick question:

if a lot of people messed up the January paper, there are bound to be lower grade boundaries, so when we do get our results, will they be the results after edexcel has set all their boundaries and made allowances?!
if so, then what's the point of re-taking the exam in June?

i'm sorry i'm just very confused with this whole concept
middle of march; you will get the UMS mark this will have already been scaled.
17. (Original post by kosy91)
please guys STOP GIVING EXPLANATIONS FOR Q8 AND THE RANGE QUESTION!!!!

i am sick and tired of different people asking for the answers, then others explaining, then again counter-arguments.

Arsey has given the explanation which is full and final.

just scroll back a few pages and read the posts instead of asking the same questions again and again
Nothing can be changed now.

http://www.wolframalpha.com/input/?i...%5E2%29%29%2B3

judge for yourself if it is fg(x) >=3
Believe what you like but I am telling you the answer is >3 NOT >=3. I am not going to explain why again.

what you have linked is correct but that has not taken into account of the domain of the function g which matters!
i hope it is 58-57 for an A, so that for 90UMS it will be 65-64
I hope 65 will be 90UMS, doubt it though.
20. If you make like one mistake....could you get a hundred? One of my friends told me taht....though i don't see the reason
21. on the very last question i found fg(x) correctly but got the range wrong, i think i wrote >4. out of those three marks, how many will i get?

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