Edexcel Mathematics: Core C1 6663 17th May 2017 [Exam Discussion]

I've updated the thread guys, bloody hell - that Latex took me over 1 hours lmao :'(.

Equations of a straight line: y = mx + c or ax + by + c = 0 (a, b and c are integers).

The gradient of perpendicular lines is equal to -1.

or $\frac{y-y1}{y2-y1} = \frac{x-x1}{x2-x1}$

If dy/dx = $x^n$, then y = $\frac{1}{n+1}x^{n+1} + c$

$\int {x^n}\ dx = \frac{x^{n+1}}{n+1} + c$

Few things -


$a,b,c$ don't necessarily have to be integers, they can be in $\mathbb{R}$



Did you mean to say that the product of two gradients which are perpendicular to one another is -1? This does not make sense as it stands.




What are $x_1, x_2, y_1, y_2$??

These two mean the same thing, you also need to comment that this is only true if $n \neq -1$


Other than that I will fix some LaTex here and there

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Edexcel has a formula booklet...

Welcome to the massive C1 preperation thread for Edexcel, though other exam boards or students can use it for practice. The reason why I didn't include OCR or other exam boards is because they usually have Edexcel C2 content in their C1 content.

This is the place to discuss, post problems, or ask any questions you may have regarding the exam!

If your post or question gets missed or no one replies to it, you can ask these people individually who are willing to help: @Cryptokyo @Zacken @crashMATHS @RDKGames @B_9710 @xzh

If anyone would like to be tagged in this thread (helpers) who are willing to help students with problems, can they please quote me and I'll tag them at the start of the post so people know who to tag if this thread ever becomes inactive.

In essence, I would really like students to post the most difficult questions they've encountered or tricky ones (with confusing wording) or ones that are not straightforward because these are the ones which often make a student panic - simply because they don't understand the content well enough or are unsure about how to answer the question due to its style.


CAN PEOPLE PLEASE POST LINKS TO REVISION RESOURCES OR ANY SPECIAL PAPERS THEY HAVE (EXCEPT EDEXCEL OR OTHER EXAM BOARDS C1 2016 FOR NOW) OR ANY MATERIALS THAT WOULD CONTRIBUTE TO THE THREAD. THANK YOU VERY MUCH!!

Edexcel C1 Exam Date - 17 MAY 2017

Revision Resources:

Exam Solutions C1 Videos
Exam Solutions C1 Papers
crashMATHS Practice Papers (credit to @crashMATHS )
Edexcel A-level Maths Section (past papers, specification etc)
Various C1 resources
Various C2 resources
M4ths
Khan Academy (generalised, you have to search for topics)
Daily revision sheets for C1 (complete one per day, each sheet dated)
Maths videos by Jayates
MyMaths
MrBartonMaths C1
MrBartonMaths C2

Credit to @Cryptokyo for this excellent resource, also attached in this post too.

All the formula/rules for Edexcel C1:

$a^m * a^n = a^{m+n}[br] a^m / a^n = a^{m-n}[br](a^m)^n = a^{mn}[br]a^{-m} = \frac {1}{a^m}[br]a^{\frac {1}{m}} = \sqrt[m]{a}[br]a^{\frac {n}{m}} = \sqrt[m]{a^n}[br]a^0 = 1[br] x^2 - y^2 = (x+y)(x-y)[br]\sqrt{ab} = \sqrt a * \sqrt b[br]\sqrt \frac{a}{b} = \frac {\sqrt {a}}{\sqrt {b}}$

For rationalising surds, fractions in the form:

$\sqrt \frac {1}{a} = \frac {1}{\sqrt a} = \frac {*\sqrt a}{*\sqrt a}[br]\dfrac {1}{a+ \sqrt{b}} = \dfrac {*a- \sqrt{b}}{*a-\sqrt{b}}[br] \dfrac {1}{a- \sqrt{b}}\ = \dfrac {*a+ \sqrt{b}}{*a+\sqrt{b}} [br]$

$x^2 + bx = (x+b/2)^2 - (b/2)^2[br]x = \dfrac{-b \pm \sqrt{b^2-4ac}}{2a}$
Discriminant (d) = $b^2 - 4ac$
d < 0 = no real roots
d = 0 = equal roots
d > 0 = two real roots (distinct roots)

You should know the transformations of graphs.

Equations of a straight line: y = mx + c or ax + by + c = 0 (a, b and c are integers).
Parallel lines have the same gradient. The gradient of perpendicular lines is equal to -1.
Perpendicular lines have gradients -1/m.

Gradient of a line: m = $\frac {y2 - y1}{x2-x1}$ - difference in y coordinates / difference in x coordinates
Equation of line formulae: y - y1 = m(x-x1)
or $\frac{y-y1}{y2-y1} = \frac{x-x1}{x2-x1}$

nth term of an arithmetic series = a + (n-1)d
Sum of an arithmetic series = n/2[2a + (n-1)d] or n/2[a+L]
where a is the first term, d is the common difference between the terms, n is the number of terms in the series and L is the last term in the series.

If y = $x^n$, then dy/dx = $nx^{n-1}$
If y = $ax^n$, then dy/dx = $nax^{n-1}$
If dy/dx = $x^n$, then y = $\frac{1}{n+1}x^{n+1} + c$
If dy/dx = $kx^n$, then y = $\frac{kx^{n+1}}{n+1} + c$
$\int {x^n}\ dx = \frac{x^{n+1}}{n+1} + c$

Difficult questions:

Layout:-

Question -
Hint -
Solution - (if you want to provide it) as many people will post solutions eventually and there may be different solutions to the same question.

I'll be posting each question with a hint and solution in the spoiler so that students can attempt the question before looking at the answer. Just remember, if you directly look at the answer, you're only cheating yourself!

Isn't C1 and C2 part of AS?
Coz I'm studying them and it's AS. To be more appropriate, I'm studying IALs so that makes it as C12, but could I join in, if you don't mind?
Coz the books are the same, aren't they? Only the exam dates differ.

That was my fault - I changed the forum title for the OP but made a mistake. I've fixed it now.

And of course you're welcome to join in

For non-IAL students I recommend trying the C12 past papers if you're aiming for a high grade since they often have harder questions.

Oh, I see
Thanks a lot!
Is practicing C1 and C2 papers beneficial for IAL students?

Now this is probably an extension question since it uses limits that isn't really discussed anyway at AS. This also used C2 as well - binomial theorem. I think this is a decent question because it actually tells us what the derivative is by its definition.

$\text{Given that the definition of the derivative } f' \text{of a function } f \text{ is given as}$
$\displaystyle \lim_{h\to 0} \frac{f(x+h)-f(x)}{h}$,
$\text{show that the derivative of } f \text{ when } f(x)=x^n \text{ is } nx^{n-1}$.

First principles actually show up within the new specification, interestingly.

I'm in Year 13 and will be resitting C1 this year because I only got 78 UMS last year due to running out of time on the last two questions .

I'll be doing the IYGB papers for practice, which I haven't seen mentioned here yet but I highly recommend them!
http://www.madasmaths.com/archive_iygb_practice_papers_c1_practice_papers.html

I'm in Year 13 and will be resitting C1 this year because I only got 78 UMS last year due to running out of time on the last two questions .

I'll be doing the IYGB papers for practice, which I haven't seen mentioned here yet but I highly recommend them!
http://www.madasmaths.com/archive_iygb_practice_papers_c1_practice_papers.html

I think it's very weird to introduce the definition of the derivative without even talking about what a limit means or what it means for a function to be differentiable and/or continuous.