Edexcel A2 C4 Mathematics June 2015 - Official Thread

ohhh sorry, my bad - i think i read in the spec that we will not be expected to form D.E's but I'm not entirely sure. Those examples such as yours above however should be fairly straightforward.

Ye it didn't look too hard but I got it wrong at first. Nice one anyway

Reply 1321

jubilant_joej

1

Original post by Iridann

You might be asked to? I don't know, I've been doing it in the Solomon papers. I know it's definitely a possibility in FP2 but I don't know for C4. I would just say best to have a little practice just in case though lol.

Ye going to have a look at a few questions. Cheers

Reply 1322

dominicwild

6

Original post by a.a.k

I dont know what i am doing but i think u can implicit differentiate 3^xy.

Am i right/wrong?

Posted from TSR Mobile

I did it this way.

Unparseable latex formula:

[br]3^x^y[br]3^x^y\ln(3) (y+x(\dfrac{dy}{dx}))[br]

Where I just used the chain rule. Differentiate the outside function, which would give

Unparseable latex formula:

3^x^y\ln(3)

and then differentiating the inside function

(y+x(\dfrac{dy}{dx}))

Reply 1323

username1200599

12

Original post by dominicwild

I did it this way.

Unparseable latex formula:

[br]3^x^y[br]3^x^y\ln(3) (y+x(\dfrac{dy}{dx}))[br]

Where I just used the chain rule. Differentiate the outside function, which would give

Unparseable latex formula:

3^x^y\ln(3)

and then differentiating the inside function

(y+x(\dfrac{dy}{dx}))

Yup that's what I did. Both our answers check out with Wolfram as well.

Reply 1324

themorninglight

10

Hi guys, so I'm a bit confused about this question, January 2014 question 5:

https://a086a5a2f39bda93734c56a63fab1d7be0a9ba38.googledrive.com/host/0B1ZiqBksUHNYQXE5T2xiNDBRd2s/January%202014%20(IAL)%20QP%20-%20C4%20Edexcel.pdf

The mark scheme has c = 1/4 (which I can't seem to get), and I've just had a look at Arsey's model answers and he has c = -1/4 but his answer at the end matches the mark scheme. Does this mean you can get a different value for c and still get the marks somehow?

Reply 1325

Kevin De Bruyne

21

Original post by themorninglight

Hi guys, so I'm a bit confused about this question, January 2014 question 5:

https://a086a5a2f39bda93734c56a63fab1d7be0a9ba38.googledrive.com/host/0B1ZiqBksUHNYQXE5T2xiNDBRd2s/January%202014%20(IAL)%20QP%20-%20C4%20Edexcel.pdf

The mark scheme has c = 1/4 (which I can't seem to get), and I've just had a look at Arsey's model answers and he has c = -1/4 but his answer at the end matches the mark scheme. Does this mean you can get a different value for c and still get the marks somehow?

I imagine the difference comes where they've changed the sign. At some point one might have +c and the other -c, so for the first one overall it would be +1/4 and the second one would be -(-1/4), which is also 1/4. (This explanation doesn't seem to be very helpful. I suppose if you had -(b-y) = y+c, where c = -b... :erm:

)

Which bit are you getting stuck on?

(edited 8 years ago)

Reply 1326

Gome44

10

Original post by 1 8 13 20 42

Dunno if anyone's still interested in solving this so I'll put spoilers

Spoiler

You can also do it by complex numbers as well if you're interested :smile:

Reply 1327

curtiscowan10

Haven't started revising for this yet and have barely even learnt the course this year... Probablity of getting a b in this exam?😂🔫

Reply 1328

Leking9

11

C4 June 2014 (R) Q7b. How do I solve for 'k' - the mark scheme is very unclear

Reply 1329

TeeEm

19

Original post by curtiscowan10

Haven't started revising for this yet and have barely even learnt the course this year... Probablity of getting a b in this exam?😂🔫

...

Original post by Leking9

C4 June 2014 (R) Q7b. How do I solve for 'k' - the mark scheme is very unclear

I'm assuming you divide by to so you're left with e^-k = .......
Then you just take natural logs of both sides which gives you what -k equals then just x by -1 on both sides to get k

Posted from TSR Mobile

Reply 1331

alibland

4

Original post by Leking9

C4 June 2014 (R) Q7b. How do I solve for 'k' - the mark scheme is very unclear

I'm assuming you divide by 2 so you're left with e^-k = .......
Then you just take natural logs of both sides which gives you what -k equals then just multiply by -1 on both sides to get k

Posted from TSR Mobile

Reply 1332

TeeEm

19

Original post by alibland

I'm assuming you divide by 2 so you're left with e^-k = .......
Then you just take natural logs of both sides which gives you what -k equals then just multiply by -1 on both sides to get k

Posted from TSR Mobile

Original post by Leking9

C4 June 2014 (R) Q7b. How do I solve for 'k' - the mark scheme is very unclear

any good?

C4R, June 2014, page 5.jpg520.6KB

Reply 1333

NikolaT

15

Original post by curtiscowan10

Haven't started revising for this yet and have barely even learnt the course this year... Probablity of getting a b in this exam?😂🔫

ExamSolutions will be your best friend over the next couple of days.

Reply 1334

Gilo98

14

Original post by TeeEm

...

What, in your opinion, is the hardest Q edexcel could throw us in C4? Horrible integration? Dodgy vector Q?

Reply 1335

NikolaT

15

Original post by Gilo98

What, in your opinion, is the hardest Q edexcel could throw us in C4? Horrible integration? Dodgy vector Q?

The vector equation of a line is 3i -4j +5k. Find the total volume of the solid formed when it's rotated 2pi around the k axis.

(Yes, I'm joking, couldn't resist.)

Reply 1336

Leking9

11

Original post by TeeEm

any good?

Yeah, perfect. Thanks

Reply 1337

TeeEm

19

Original post by Leking9

Yeah, perfect. Thanks

no worries

Reply 1338

Gilo98

14

Original post by NikolaT

The vector equation of a line is 3i -4j +5k. Find the total volume of the solid formed when it's rotated 2pi around the k axis.

(Yes, I'm joking, couldn't resist.)

Oh my god I **** myself before i saw the last bit.....wouldn't put it past edexcel tbh