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Further Maths AQA GCSE exams

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Reply 40
Avatar for Notnek
Notnek
21
Original post by NiamhM1801
And I thought that √9 could be 3 or -3? As (-3)² is 9?

This is a common source of confusion for students, teachers and even textbooks.

This explains things.
Reply 41
Avatar for Zacken
Zacken
22
Original post by Ano123
Hi, I need help on a particularly awkward question.
The question is :

Simplify fully the expression

3x3x2×9x2 \displaystyle \frac{3x^3}{x^2} \times \sqrt{\frac{9}{x^2}} .
I get an answer but it's just cant be right.
Could someone quickly just post an answer so I can see if I'm right?
Thank you!


Call it f(x)f(x), then:

Unparseable latex formula:

\displaystyle f(x) = \begin{cases} 9 \, & \text{for } x > 0 \\ -9 \, &\text{for } x < 0

Reply 42
Avatar for Notnek
Notnek
21
Original post by Ano123
Hi, I need help on a particularly awkward question.
The question is :

Simplify fully the expression

3x3x2×9x2 \displaystyle \frac{3x^3}{x^2} \times \sqrt{\frac{9}{x^2}} .
I get an answer but it's just cant be right.
Could someone quickly just post an answer so I can see if I'm right?
Thank you!

Where did you get this question from? Textbook? Past paper?
Reply 43
Avatar for Ano123
Ano123
15
Original post by notnek
Where did you get this question from? Textbook? Past paper?


Just made it up.
Wtf you're getting an extra GCSE for this **** which the IGCSE tests you on.
Reply 45
Avatar for Notnek
Notnek
21
Original post by Ano123
Just made it up.

OK - I doubt that it would be in a FM GCSE paper.
Reply 46
Avatar for Notnek
Notnek
21
Original post by _Xenon_
Wtf you're getting an extra GCSE for this **** which the IGCSE tests you on.

AQA FM is a much harder than IGCSE (CIE and Edexcel).
Original post by notnek
AQA FM is a much harder than IGCSE (CIE and Edexcel).


I have never seen an IGCSE paper, but tbh looking at the specification there is a fair amount of overlap with the AQA FM course, and some stuff on it that i don't recall being on the fm course but it all comes down to how hard the questions are tbh
Reply 48
Avatar for Notnek
Notnek
21
Original post by samb1234
I have never seen an IGCSE paper, but tbh looking at the specification there is a fair amount of overlap with the AQA FM course, and some stuff on it that i don't recall being on the fm course but it all comes down to how hard the questions are tbh

There is some overlap but the difficulty of the questions in AQA FM are in a different league.
Original post by notnek
There is some overlap but the difficulty of the questions in AQA FM are in a different league.


I'll take your word for it, I did AQA FM and GCSE too long ago to really be able to tell how difficult they are anymore
Original post by notnek
There is some overlap but the difficulty of the questions in AQA FM are in a different league.


Yep IGCSE are many many times tougher questions, I agree.
Reply 51
Avatar for Notnek
Notnek
21
Original post by _Xenon_
Yep IGCSE are many many times tougher questions, I agree.

I think most of the people taking FM would wish this was true :smile:
Original post by notnek
I think most of the people taking FM would wish this was true :smile:


FM A level?
Reply 53
Avatar for Notnek
Notnek
21
Original post by _Xenon_
FM A level?

No. AQA Level 2 Further Maths. Which is what this thread is about.
(edited 7 years ago)
Original post by notnek
No. AQA Level 2 Further Maths. Which is what this thread is about.


But can you please help me with differentiation? :-)
Reply 55
Avatar for Notnek
Notnek
21
Original post by _Xenon_
But can you please help me with differentiation? :-)

Not here. Ask in the maths forum.
Original post by notnek
Not here. Ask in the maths forum.


OK but please reply OK? :smile:

Thanks
Original post by Ano123
Not quite. 9=3 \sqrt 9 = 3 .
9≠−3 \sqrt 9 \neq -3 .
What's actually happening here is you made a mistake when square rooting
x^2 . If you put any negative number as x into the expression, say -1 you get (−1)2=1=1 \sqrt {(-1)^2} = \sqrt 1 = 1 . So as you can see if x is a negative number then it returns a positive number.
So actually x2=∣x∣ \sqrt {x^2} = | x | .
The vertical lines mean the absolute value. Meaning we just take the magnitude of the number. So |-2| = 2.
|-100|=100 etc.

So, the answer to the original question is 9 and -9?
Reply 58
Avatar for Ano123
Ano123
15
Original post by Ishan_2000
So, the answer to the original question is 9 and -9?


Yes it is -9 for x<0 and 9 for x>0. You can't just say 9 and -9 without stating when it is one or the other,
Reply 59
Avatar for Notnek
Notnek
21
Original post by Ishan_2000
So, the answer to the original question is 9 and -9?

What was the original question?

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