Further Maths GCSE AQA Paper 1 (Unofficial mark scheme)

Never mind I'm wrong - wish I'd had time to check!!!

Reply 21

Original post by Torticci

Can someone explain the limiting factor one and how it was 3/5? I though it was 2.4 cos then the denominator would equal 0 and the fraction would be undefined

Posted from TSR Mobile

Limiting factor's really easy.
Start by dividing everything by the highest power of n (in this case it was just n)
You'd have got 3/5+(12/n). As n increases, 12/n gets smaller and smaller (closer and closer to 0) so it can be ignored.
Hence 3/5.

Reply 22

Original post by ErinMei

That is just an A* distinction i think depending on grade boundaries. I think i got 55 marks at the least

Posted from TSR Mobile

I thought you got like 65 or something xD!

Original post by Redcoats

Which question was the x = -55 ?

It was on the question where you had the brackets and then to the power of a third.
Solve for x

Original post by NiamhM1801

For the inequality, t asked for integer solutions. Wouldn't you therefore have had to put 9, 10 and 11?
Other than that and question 6 (which I knew I'd completely messed up) I think I've done very well :biggrin:

Yeah, I read the question wrong... I'm so struggling these days with just reading questions correctly :angry:

Original post by NiamhM1801

Oh, also I didn't get +75x for the cubic, I got +25x. I'm probably wrong though haha

It was (x-5)^3 I think and the answer is +75x so I think you got it wrong :frown:

Reply 23

Original post by NiamhM1801

Never mind I'm wrong - wish I'd had time to check!!!

Don't worry, I thought I was running out of time - so I rushed it - only to realise I had 30 or so minutes to spare.

Reply 24

Original post by Torticci

Can someone explain the limiting factor one and how it was 3/5? I though it was 2.4 cos then the denominator would equal 0 and the fraction would be undefined

Posted from TSR Mobile

The nth term was 3n / 5n +12

Factor out n : n(3)/ n(5+12/n)

Cancel out the n's: 3 / (5 + 12/n)

Substitute infinity: 3/ (5 + 12 / infinity)

12 / infinity tends towards 0 so: 3 / 5 + 0

Therefore the limiting value is 3 / 5

Reply 25

Original post by Chittesh14

I thought you got like 65 or something xD!

It was on the question where you had the brackets and then to the power of a third.
Solve for x

Yeah, I read the question wrong... I'm so struggling these days with just reading questions correctly :angry:

.

It was (x-5)^3 I think and the answer is +75x so I think you got it wrong :frown:

Pretty sure it was x = 121 for the power of a third question : (3- sqrt(x))^1/3 = -2 or something

(edited 7 years ago)

Reply 26

Original post by Chittesh14

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It was (x-5)^3 I think and the answer is +75x so I think you got it wrong :frown:

Original post by Chittesh14

Don't worry, I thought I was running out of time - so I rushed it - only to realise I had 30 or so minutes to spare.

Oh don't worry we all are - in biology today in the thing that asked about lifestyle factors I talked about medical history and in the one that asked about medical history I made stuff up as I couldn't remember anything about medical history!!

And I know, our clock didn't get reset so it finished on 2:46, really hard to judge your timings like that! And at least it wasn't the other way round!

Reply 27

Original post by Redcoats

Pretty sure it was x = 45 for the power of a third question : (3- sqrt(x))^1/3 = -2 or something

I definitely got 55, not sure about the positive or negative though.

Reply 28

Torticci

Thanks for the limiting factor help!

Posted from TSR Mobile

Reply 29

Original post by Redcoats

Pretty sure it was x = 121 for the power of a third question : (3- sqrt(x))^1/3 = -2 or something

No idea man, we can only tell once we know the exact question again :s-smilie:

.
All I remember is 9 - 64 = x lol.

Reply 30

Original post by NiamhM1801

I definitely got 55, not sure about the positive or negative though.

Sorry not 45, x = 121. Check for yourself, it works!

(3 - sqrt(x))^1/3 = -2

3 - sqrt(x) = -8

- sqrt(x) = -11

sqrt(x) = 11

Therefore x = 11²

So x = 121

Reply 31

Original post by Redcoats

Sorry not 45, x = 121. Check for yourself, it works!

(3 - sqrt(x))^1/3 = -2

3 - sqrt(x) = -8

- sqrt(x) = -11

sqrt(x) = 11

Therefore x = 11²

So x = 121

Mathway says the same haha, what did I do so wrong lmao

Reply 32

Original post by Chittesh14

No idea man, we can only tell once we know the exact question again :s-smilie:

.
All I remember is 9 - 64 = x lol.

Are you sure your not mixing up questions, i.e. are you thinking of the cos theta or sqrt(125) + sqrt(20) = sqrt(80) + sqrt(x) where x = 45 question? The exact question, I'm pretty sure, is
(3 - sqrt(x))^1/3 = -2, solve for x.

(edited 7 years ago)

Reply 33

Original post by NiamhM1801

Mathway says the same haha, what did I do so wrong lmao

Don't worry! What do you think your mark will be out of 70?

Reply 34

My method:
(3-√x)¹/₃ = -2
3-√x = -8
9-x= 64
64-9=-x=55
x=-55

Reply 35

Original post by Redcoats

Don't worry! What do you think your mark will be out of 70?

I'm not sure as the marks aren't given, however this has certainly boosted my confidence! Definitely think between 55 and 60 which, although my lowest score yet (I owe this to nerves as I did panic near the start), I'm quite proud of.

Reply 36

Original post by NiamhM1801

Mathway says the same haha, what did I do so wrong lmao

We both ****ed up lol.

Original post by Redcoats

Sorry not 45, x = 121. Check for yourself, it works!

(3 - sqrt(x))^1/3 = -2

3 - sqrt(x) = -8

- sqrt(x) = -11

sqrt(x) = 11

Therefore x = 11²

So x = 121

That's weird though, what I did and probably NiamhM too:

(3 - sqrt(x))^1/3 = -2

(3^1/3 - x ^1/6) = -2
9 - x = 64
x = -55

Original post by Redcoats

Nah I got 45 for that, and -55 for this - I'm wrong, you're right. I'm dead.

Reply 37

Original post by NiamhM1801

My method:
(3-√x)¹/₃ = -2
3-√x = -8
9-x= 64
64-9=-x=55
x=-55

I'm not too sure about your method because:

First, x cannot equal a negative number as you're square rooting it.

Secondly, when you squared both sides of the equation in 3 - sqrt(x) = -8, you square rooted incorrectly:

Square rooting both sides gives: (3-sqrt(x))² = (-8)²

This is : (9 - 6sqrt(x) +x) = 64 as it is a double bracket, you can't just square each term as you have done.

Really sorry to tell you this! I'm sure you've still got your A^ - remember the boundaries for such are really low

Reply 38