Edexcel C2 20th May 2015 *Official Thread*

any one who coould help me on the a and b partt??

Original post by lulupixie

Oh good 😂😂😂 sorry I just assumed everyone did stats and ignores the D1 etc 😂😂😂 I find stats easy tbh, if I could just continue with stats next year and leave the core behind I would but I don't think you can do that unfortunately 😂🙈 how do you find it? It's my last exam so I hope I will have energy left by then but I have half term to revise still 😊

Hahah, no that's absolutely fine- no need to apologise lol. 😂😂 Thats great! Yeah- most of stats is good!! Although I hate the fact that a small incorrection when inserting the numbers into the calculator can wreck everything bc its all v follow on..if that makes sense. For example in standard deviation stuff..otherwise it's straightforward. :smile:

Yeah, I was debating as to whether I should do M1 next year but I think I'll be doing stats too.
Hahah!- yes me too, hopefully you will. :smile:

Posted from TSR Mobile

Reply 302

userxx990

part a, whats the liner factor?

and in parrt b how do we factorise this thing?

Original post by userxx990

any one who coould help me on the a and b partt??

Reply 303

frances98

Original post by AngelaMckenzie

ambiguous case
what the hell is that!

Oh I've heard of that! I think it's something to do with trigonometry

Posted from TSR Mobile

Reply 304

Hai_Ann

4

Does anyone know the difference between stationary points and turning points? Lol.

Also does anyone know what formulas we may need to know for optimisation questions such as 'volume of cuboid' etc...

Reply 305

lulupixie

Original post by Anon_98

Hahah, no that's absolutely fine- no need to apologise lol. �� Thats great! Yeah- most of stats is good!! Although I hate the fact that a small incorrection when inserting the numbers into the calculator can wreck everything bc its all v follow on..if that makes sense. For example in standard deviation stuff..otherwise it's straightforward. :smile:

Yeah, I was debating as to whether I should do M1 next year but I think I'll be doing stats too.
Hahah!- yes me too, hopefully you will. :smile:

Posted from TSR Mobile

Yeah everything needs to be checked double checked and triple checked! I don't like it when they are sneaky or make a question really long because I lose interest half way through 😂🙈 you're probably wondering why do I do English then but it's only maths I get bored with 🙈

Reply 306

Original post by Hai_Ann

Does anyone know the difference between stationary points and turning points? Lol.

Also does anyone know what formulas we may need to know for optimisation questions such as 'volume of cuboid' etc...

I thought these were the same thing- but just different terms used. I'm not entirely sure but dy/dx=0 for stationery points and turning points right? Loll, I am so wrong with this..😂
Wait- isnt turning/max/min/stationery points all the same thing..?

As for the formulas..We just use the basics:
Volume= Pi r^2h
A= l* w ..Etc

I'm not sure if that helped or just confused you further, sorry lol.

Posted from TSR Mobile

Reply 307

Original post by lulupixie

Yeah everything needs to be checked double checked and triple checked! I don't like it when they are sneaky or make a question really long because I lose interest half way through 😂🙈 you're probably wondering why do I do English then but it's only maths I get bored with 🙈

Oh my gosh- ikr! Haha!- so irritating. But its then usually a lot of marks so maybe its worth all the effort. Probably sound so lazy bahahah! People reading this thinking- "Oh my- effort to type numbers into a calculator"
Ahh right!- Thats strange hm bc English questions are so long and its like elaborating about the word "white" for almost a decade ahah!(I apologise if it has changed since GCSE lol)..but statistics gets so incredibly boring I agree. Probability is the absolute worst lol.

Posted from TSR Mobile

Reply 308

AJC1997

Original post by userxx990

part a, whats the liner factor?

and in parrt b how do we factorise this thing?

I can help you sir! So for part a all you need to do is insert 1 for x. The question is basically saying: 'Show that (x-1) is a factor of x^3 - 9x^2 + 24x - 16' but in a different way, kind of.

So when you insert x = 1 you get: 1^3 - 9(1)^2 + 24(1) - 16

= 1 - 9 + 24 - 16
=16 - 16, 16-16 equals 0!

Therefore (x-1) is a linear factor, as the remainder is 0.

Now part b.

you know that the first bracket is (x-1) now.

now you have to find the second bracket.

there are different ways of doing this but heres how I do it:

(x-1)(x^2 +16 )

you know that x^3 will be the first number, and + 16 the last as this will give you x^3 and - 16

now multiply out what you have, and see what the second number in the second bracket has to be:

x^3, 16x, -x^2, -16

is what you have

and the equation you need is x^3 - 9x + 24x - 16

so you need -8x^2 to get -x^2 into -9x^2

therefore the third number in the second bracket is '-8x' as this will multiply with x in the first bracket to give you the -8x^2 more you need to reach -9x^2.

so now you have: (x-1)(x^2 - 8x + 16)

now factorise the second bracket to get: (x-4)(x-4) = (x-4)^2

therefore your answer is (x-1)(x-4)^2

maybe this isn't explained well but hope it at least helps a bit! :smile:

Reply 309

LearningGeek

4

Original post by AJC1997

Guys, does anyone have some rules for the the questions where they ask you to solve for 0 < x < 360 and they give you 3sin(x+45) = 2 (for example)

I know how to do everything except the final part sometimes I get confused. I know it's 180 - x for Sin, 360 - x for Cos and 180 + x for Tan.

But in this example you do 180 - x which is fine, then minus 45 which is also fine.

But the other answer is 360 + x minus 45, why is it 360 + x is it just because 360 - x is for Cos? is there a set of rules for this?

You could perhaps look at the cast diagram method, its much easier

Posted from TSR Mobile

Reply 310

tw15st3d

17

Original post by AngelaMckenzie

ambiguous case
what the hell is that!

its like when you do the sine rule- the angle it could be, could be the one you calculated or 180 - (angle you calculated) because you could make 2 different triangles if the angle calculated is larger than the given angle.

Reply 311

studentwiz

3

Original post by Hai_Ann

Does anyone know the difference between stationary points and turning points? Lol.

Also does anyone know what formulas we may need to know for optimisation questions such as 'volume of cuboid' etc...

Original post by Anon_98

I thought these were the same thing- but just different terms used. I'm not entirely sure but dy/dx=0 for stationery points and turning points right? Loll, I am so wrong with this..
Wait- isnt turning/max/min/stationery points all the same thing..?

As for the formulas..We just use the basics:
Volume= Pi r^2h
A= l* w ..Etc

I'm not sure if that helped or just confused you further, sorry lol.

Posted from TSR Mobile

yeah what Anon_98 said about the stationary and turning points.

To work out if its a max or min you have to use the second differential and sub the value of x obtained from the stationary point. From there if the value is >0 its a minimum and if its <0 then maximum

For formulas you need to know the log rules
and area of trapezium would help
also a question on cylinders could come up so area and volume of a cylinder.

Reply 312

TeeEm

Original post by Columbo97

Considering people have been requesting a thread.

Edexcel C2 - Wednesday 20th May 2015

Hopefully this thread will motivate us all, and help us to achieve the grades we deserve.

Useful Links
Specification - http://qualifications.pearson.com/co...hs_Issue_3.pdf
Formula Booklet - http://www.edexcel.com/migrationdocu...cal-Tables.pdf
Offical Past Papers - http://www.mathspapers.co.uk/edexcel.html

Examsolutions - www.examsolutions.net
Maths247 - www.m4ths.com
Question Booklets/Past Papers - http://www.madasmaths.com

If you have any other websites you'd like to add, post them below and I'll edit this post.

Man Alive, there are 3 "official threads" for C2!!!

I have to endorse this one as it mentions my site

... and for the record before I get pestered
http://www.thestudentroom.co.uk/showthread.php?t=3327325

(edited 8 years ago)

Reply 313

Hai_Ann

4

Original post by studentwiz

yeah what Anon_98 said about the stationary and turning points.

To work out if its a max or min you have to use the second differential and sub the value of x obtained from the stationary point. From there if the value is >0 its a minimum and if its <0 then maximum

For formulas you need to know the log rules
and area of trapezium would help
also a question on cylinders could come up so area and volume of a cylinder.

Okay thanks! :smile:

Reply 314

domcandrews

Original post by Clovers

Does anyone have an easy way of working out trig identity questions?

yeah i find all the caste diagrams a bit confusing but they're good for understanding, the following method works all the time for me:

tan = add 180 to principal value, then keep adding 180 for required range
cos = 360+principal value, 360-principal value, 720+ p.v., 720-p.v. etc same for negative ranges (-360 - p.v, -360+p.v)
sin = 180-p.v., 360+p.v., 540-p.v., 720+p.v.

can try these with any trig question throughout the whole alevel course and they always work, but many people have their own methods and just stick to that.

hope this helps

Reply 315

sandy5621

How can you get two x values from sin(x) = 0.8? Ahh im confused, I don't know what my book is trying to say...

Reply 316

sandy5621

How do you get two x values from sin(x)=0.8?

Reply 317

Original post by sandy5621

How do you get two x values from sin(x)=0.8?

What's the question?

Posted from TSR Mobile

Reply 318

studentwiz

3

Original post by sandy5621

How do you get two x values from sin(x)=0.8?

use CAST diagram sin^-1(0.8) = 53.1 and 180-53.1...=126.9

Reply 319