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Thoughts on Edexcel Core 2 2015

Many people came out of this exam saying it was hard, even some of my FM class said they didn’t particularly enjoy it. Compared to the 2014  paper i do think it was a bit harder; the lack of a question concerning the trapezium rule was a noticeable omission of some easy marks. 

Starting on a question by question basis, Question 1 was a straightforward application of the binomial expansion, only requiring 3 terms to be given. This is esppecially easy as you are given the binomial expansion in the formula book! I think this was a very nice start ot the paper and hopefully would have boosted the confidence of the students sitting the paper.

  
Moving on to question 2 we had, what I think, is quite a nice circle geometry question. Finding the equation of the circle is straightforward, given that you are told the centre and a point on the circle  – conceptually I think this is easier the starting part of the equivalent question last year. We then go on to find the equation of a tangent to the circle requiring a bit of memory of circle theorems from GCSE and the properties of perpendicular lines.

Some students that I have spoken to have said that they found Question 3 hard, it is definitely more challenging than the equivalent 2014 question, however it is almost identical to the corresponding question in the 2013 paper. Just use the remainder theorem and factor theorem to form two equations in terms of \(a\) and \(b\) and then solve. It factorises nicely, into the factor given and a differenc of two squares (as long as you recognise that a factor of 3 can be pulled out).

  
The area and perimeter of sectors question (Question 4) seems fairly typical to me, I think some may have found the first part of the question a bit tricky, and won’t have thought to break the triangle into two right angled triangles and then double it. Once the angles have been calculated, completing the rest of the calculation is fairly simple. I guess some may have forgotten to add the base length in when calculating the perimeter. Please marvel at my awful diagram for this question, and note I used the incorrect angle for the last part at first!

  
Question 5 concerned geometric series and to me feels harder than the equivalent question last year. However, as the formulae are all given in the formula book, forming the equations (simultaneous equations again!) required for the first part shouldn’t be too difficult, and solving them drops out nicely.  The second part of this qquestion requires a bit more thought and the use of logarithms to efficiently solve  – I also think a few people will have forgotten to round up to the nearest integer.

   
  
Question 6 moved on to integration and finding the area under a curve. They even gave you the points where the curve crossed the axis and a very helpful picture  of the shaded region to find the area. The tricky part I imagine would be remembering to take the absolute value of the area of the first region when working out the total area.

  
Question 7 was the main logarithm question and I think this was slightly easier than the last two years as it was obviously a logarithm question and no curve sketching was required. As long as students are systematic in their application of the logarithm rules part b should be ok, though there are plenty of places for arithmetic errors to creep in.

 
I think the trigonometry question will have thrown a few people: you don’t often see \(3\theta\) in a question, but apart from that part a is ok as long as they remember the period of \(\tan (3\theta) \)  is a third of that of the period of \(\tan ( \theta) \). The phrasing of part b seems to have confused a few people, but once you have got to a quadratic in \( \cos x \) the solutions drop out nicely. 

The final question was very similar to the last question on the 2014 paper – in that it concerned minimising a function of the surface area of a 3D shape. Minimising it and checking the nature of the stationary point is straightforward and these marks could be picked up even if the candidate hadn’t managed to derive the expression for the cost of polishing themselves.

   
 
 

Overall a nice paper, a bit more challenging than some recent ones in places but generally it seemed pretty fair. They are liking simultaneous equations at the moment.

A scan of the questions is here and a pdf of my solutions (complete with my incorrect attempt of Q5b) available here.

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A Level Teaching

Partial Fractions

As I teach Further Maths I haven’t really considered how I would teach partial fractions, and normally just do them in my head without writing down any workings.

However, I have recently started providing some last minute tuition and one of the things they wanted explaining was partial fractions. To be honest I have forgotten how I was taught this, I have a feeling it was the “substitute different x values in to knock out terms” method. I went through two slightly different methods for the partial fraction shown below

  
Personally I prefer Method 1 but I think Method 2 would probably be better for the weaker students as it shows explicitly what is happening. 

How do other people teach this?

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Thoughts on Edexcel Core 1 2015

I don’t actually teach Core 1, but as I’m trying to do every A level maths paper sat by students at my school I thought I’d post a few reflections after I had done it. A pdf of my solutions are here respectively.

Overall it seems to have been found pretty easy by the stronger candidates doing Further Mathematics but weaker candidates seem to have found it a bit more difficult. After having done the paper I think that it is fairly straightforward if your algebra skills are good, most questions are clear applications of clearly specified bits of knowledge.

Question 1 was just a bit of manipulation of surds, with the first part used in the second  with quite a nice rationalising the deonominator question. Question 2 was essentially a GCSE qustion – a 7 mark gift to people sitting this exam.  
 

Question 3 was a straightforward test of basic integration and differentiation skills. I think question 4 may have thrown a few people – when I first looked at it I thought I couldn’t do it – but as soon as you do the first part and find a few terms, finding the sum is straightforward. 

 

  Question 5 tests knowledge of the discriminant; I think the fact that the inequality you have to show is a greater than may confuse a few people, and when it comes to finding the set of possible values of p a lot of people will probably apply the quadratic formula instead of completing the square which is (as always) easier.

 
Question 6 is straightforward, nothing challenging there, they just have to do it. Question 7 I like  and is  straight forward when you consider the laws of indices – yet another easy quadratic to factorise. I think the final step may confuse people if they haven’t done something similar before. 

   
 

For Question 8  we have yet another quadratic that factorises (I’m getting a bit bored of these now…), and then a graph to sketch.  I still find it strange that identifying stationary points isn’t in Core 1.

 

Question 9 was a nice application of the formulae for arithmetic progressions. The last part did at least expect some thought on how to calculate the total which made it a bit more interesting.

  
Question 10 was probably the trickiest question, in my opinion, on the paper – the last part is certain to have thrown some people and required more thought than a simple “find the normal” paper. 

  
Overall I thought this was a very fair and accessible paper.

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Thoughts on Edexcel Further Pure 1 2015

My students weren’t very happy with this years FP1 exam and found it harder than past papers. After doing the paper, I agree it seems harder than recent past papers but I think it was a fair paper.

Questions 1 and 2 I thought were incredibly straight froward (5 marks for factorising a cubic and solving a quadratic seems generous), though I was surprised and saddened that there was no Newton-Raphson in the numberical-methods section.  

Questions 3 and 4 were nice too, the summations in 3 dropped out quite nicely, and 4 was a straight forward test of basic definitions for complex numbers.

   


Question 5 concerned the hyperbola, and wasa nice test of the basics of finding normals and points of intersection – not much to trip people up here I didn’t think.

  

There were two induction proofs for question 6 (no divisibility question though, which everyone I have spoken too seemed pleased about. I feel that these were a bit trickier than similar induction questions in previous years, with the algebraic manipulation to complete step 3 being not as straightforward (in that you couldn’t immediately factorise out some of the terms for the summation proof, for example) as sometimes.

   
 

I would describe Question 7 as a gift of a question. I can’t really believe they explicitly asked youto find the inverse of the matrix B, before it needed to be used to work out the coordinates of the triangle T. I think this should eliminate the possibility of candidates using the wrong matrix in this question.

  
Oddly this paper had only 8 questions, I have got used to the FP1 exam having 9.  The final question was however worth 14 marks and was trickier than a lot of conics questions. I guess the main reason that it seemed trickier was due to the wording of the question and the fact that the last part of the question wasn’t splt into multiple sections. Once you got past the wroding and the similarity of the letters p and q I thought this was quite a satisfying question, and I liked the result you were asked to show in the last part.

   

 

Please excuse the strange coloured triangles across the photos, it seems to be an odd artefact of the Office Lens app. 

Update: Click here to download a pdf of my solutions and here for a scan of the questions. 

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Books

This post was going to be more involved…. 

Last week a few of us were sharing photos of our collections of maths books and for some reason I couldn’t post more than one photo on a tweet! So, I said I’d write a blog post – I was originally going to write about about some of my favourites, but being short of time tonight I think I will leave that and some of them may make it into my “Classic Maths Books” series. 

My books are seemingly spread all over various book shelves, and some just haven’t made it on to shelves (or I have let people borrow them and when they have come back their shelf space has been taken by something new) so below are photos showing all (I think) of them:

   
            

  

  

  

  

  

  

  

  

 

I think I may catalogue them over half term as there are quite a few here I had forgotten that I had…

Are there any that people would recommend I get etc?

I do think it would be good to have a central review of books and some of the nice things they contain or a lending system to spread our collective libraries around. 

 

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Closed Questions – An ATM Session

This Saturday I went to a great session organised by the East Midland’s branch of the Association of Teachers of Mathematics. It was led by Colin Foster of The University of Nottingham who was talking about “Rich Mahematics from Closed Questions”.

Writing about the session in a no-linear fashion I liked how he used Fermat’s Last Theorem as an example of a yes-no question (often seen as a closed question) leading to rich mathematics.

  
A closed question is often defined as a question with one correct answer and no scope for discussion. The open vs closed question idea is something that is discussed often, with closed questions being seen as inferior to openquestions and not readily leading to rich mathematics.  The aim of this session was to show that rich mathematics can come out of closed questions.

I liked the initial question of \( 15 \times 823 \). This works out to be 12345. I think this could be a nice launch point for a lesson, looking at other similar sums, divisibility rules etc.

Colin then made the point that two closed questions together or a sequence of closed questions can be a good prompt to some interesting maths. He first gave two quadratics \(x^2+7x+6\) and \(2x^2+7x+6\); both of these quadratics can factorise. Then the prompt questions could be things like “Is this a fluke?”, “What can we say about how to make these?”. I confess I haven’t figured this out yet, so will probably write about it when I do.

As an example of a sequence of questions consider the following:

  • How many factors does 10 have?
  • How many factors does 100 have?
  • How many factors does 1000 have?
  • How many factors does 10000 have?

I started by manually listing factors, and soon noticed a pattern of the square numbers appearing. It becomes much clearer when you realise that \(10 = 2 \times 5 \), \(100 = (2 \times 5)^2 = 2^2 \times 5^2 \), \( 1000 = 2^3 \times 5^3 \) and so the factors can be computed using a two-way table

  
There are many opportunities for students with this task including practise at finding factors, spotting number patterns, predicting future terms of the sequence, generating nth term rules and investigating how the factors of other sequences grow (for example 6,60,160,1600 and 2,4,8,16,32). Of course not everyone in the class will reach the same point, but this isn’t a problem. I really liked Colin’s justification for doing these kind of activities:

“The emphasis is on the thinking going on in the classroom, not on the kids getting to the final answer” 

This is a nice “low floor, high ceiling” task and I’m going to use it for an observed lesson later this week, and I will blog about the lesson in full towards the end of the week.

I also realised (something that in hindsight I should have known before as it is obvious) that any prime number to the the power of \( n \) has \( n+1 \) factors.
After looking at factors, Colin presented some inequalities to shade (see his paper here for more information – it’s a nice short article!) and a few problems about fitting rectangles into squares.

All in all it was a great session (it was also good to catch up briefly with Rob who is the secretary of the East Midlands Branch) and the £5 cost is a bargain.

It also reinforced the fact that I have always been irritated by the open/closed questioning distinction. An open question can just as much lead to narrow mathematics as a closed question – it’s the questioner (is that a word?!) that is important. 

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Jumping Ahead

I recently opened my copy of the TES from 17th April (this is quite good for me, I normally have months worth of these stacked up which I finally open in the holidays…) and there was a short article with an interview with Dr Geoff Smith of the University of Bath. 

I was lucky enough to have Geoff as a lecturer during my undergraduate, but in addition to being a university lecturer he is also the chairman of the British and International Maths Olympiads. In this role he meets many gifted young mathematicians, some of whom will have been pushed through the exam system quicker than their peers. 

He makes the point that this is often not for the best, and that students often look back on it as a mistake. Instead, he says that students need to be given extended problems that build on the mathematics they learn and school and goes onto to say 

“… There’s so much worthwhile mathematics to keep them happy and busy while their bodies turn into adults. School maths barely scratches the surface.”

I definitely agree with this, but I think there needs to be some kind of central provision for students like this. Some schools may not have teachers who are confident enough with off syllabus mathematics to provide these kind of problems and further exploration. There are so many great resources out there that council wide “clubs” could use. I know we have the Royal Institution Masterclasses for the younger students, but to me there seems ot be little for the older top ability (not necessarily IMO candidates) students where there isnt’ a financial cost to them. 

Sue Pope also makes the point in this this article that rushing students through could result in an  “understanding of mathematics may end up somewhat fragile”.

Finally, thefollowing quotes from Geoff Smith made me laugh:

“Someone with a short attention span shouldn’t enter this profession”, “Someone who isn’t obsessive shouldn’t go into pure mathematics”

I can see this, I can certainly be obsessive, but I’m not convinced I’m obsessive enough about one particular thing to go back into Mathematics research. To get into a successful academic post, it seems ot me that lots of sacrifices need to be made – short term contracts, willingness to move around a lot etc.

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East Midlands West MathsHub Presentation

Today I led the East Midlands West Mathshub Curriculum Development meeting. I had been asked to feedback about the fantastic presentation Jo Morgan (@mathsjem) gave at the last National Mathematics Teachers Conference (mathsconf). Her original presentation is discussed , and her subsequent posts are definitely worth a read.

My presentation is (hopefully) embedded below, and can also be viewed at this link.

[prezi id=”http://prezi.com/zcqk8rt-s0j8/?utm_campaign=share&utm_medium=copy&rc=ex0share” align=center width=600 lock_to_path=1]

It seemed to go well – I was pretty nervous with it being my first presentation to colleagues, all of whom had been teaching for longer than me – and I hope everyone there got something out of it.

I started the presentation with the following analogy that I had recently seen in the book “The Number Sense” by Stanislas Dehaene.

You are given two lists to remember, a personal address book

  1. Charlie David lives on George Avenue.
  2. Charlie George lives on Albert Zoe Avenue.
  3. George Ernie lives on Albert Bruno Avenue.

and a professional address book

  1. Charlie David works on Albert Bruno Avenue.
  2. Charlie George works on Bruno Albert Avenue.
  3. George Ernie works on Charlie Ernie Avenue.

I certainly struggle to remember this list, all the names just get far too confused. However, Stanislas has constructed this in such a way that if you replace the names with numbers then the home and professional addresses represent addition and multiplication facts. I think this is a really nice way of giving a bit of an insight as to why children with numerosity weaknesses confuse multiplication and addition facts.

Jo was kind enough to give me permission to hand out a copy of work book (which received some very positive comments) which I used in conjunction with some slight modifications to a few of her slides.

However, I decided to split the hour and a half (ended up being a bit less due to an Ofsted meeting happening at the University) into two, first of all looking at some software I have used in lessons or for resources, and some techniques I use to stretch the great group of Sixth Formers that I teach. I have been meaning to write blog posts about all of these things if I haven’t already, so hopefully this is the impetus I need to actually do this over the next few weeks – look out for them! I also briefly talked about how I believe that when teaching the numerical methods topics it is important to convey some sort of appreciation for how they would be coded, and pointed people to the post by Manan Shah (@shahlock) where he discussed how to teach programming without a computer.

Following this we looked at a few of the topics that Jo discussed in her talk, and I particularly promoted James Tanton’s website and videos. A while back – last year originally I think – I saw a method for factorising quadratics with leading order coefficients not equal to zero on a blog post by Jo (I really do pick up a lot of interesting things from her posts) and had always been a bit dubious of it. It is called the diamond method (explained in this video) and seemed a bit tricksy to me, but I used it last night during a revision session with some Year 11s who were really struggling with these and they all seemed to pick it up very quickly, and I am told one of them could demonstrate it’s use to another teacher this morning. I’m not sure I would initially teach it in this way, but it certainly seems to have its uses. Many people seemed to like the Indian method for finding out the hcf and lcm.

Please look at the presentation for further details and see the question sheet here. Also check out Jo’s posts on her presentation and topics (factorising, quadratics, highest common factor, sequences, linear graphs and surds) as we covered less than half of them tonight.

Thank you to every one who too the time out during the busy exam season to come tonight. I really enjoyed the conversations I had throughout the session, and it was interesting to see other peoples methods and view points on everything we discussed.

Categories
Books

Beautiful Knowledge – A great BBC article

On the 21st April the BBC published this great article containing extract’s from David McCandless’ book “Knowledge is Beautiful”. There are some great infographics in this article that could be used in the classroom to promote a lively discussion about presenting data, how to present data to increase understanding and how to use design to increase clarity. I particularly like the graphic showing common passwords and their realtive strength

  
I’d certainly recommend taking a look at the article and the book Knowledge is Beautiful as well as David McCandless’ earlier book Information Is Beautiful.

Categories
Teaching

My Mathematical Journey

I recently read Manan’s post and learnt that in the States April is Mathematics Awareness Month. Manan had written about his mathematical journey so I thought I would do the same.

I remember always liking maths and number stuff, but apparently for the first couple of years at primary school I wasn’t seen as being good at it because I didn’t put in a lot of effort. I can remember having very boring SPMG (I think that was the acronym) work books, where you had to do things like “colour 12 balloons” – I was never good at colouring (I still can’t really colour in between the lines to be honest) and so I just didn’t do it. I probably wasn’t the best kid to teach, as far as I was concerned I could count and I didn’t need to colour things to prove it. 

I loved primary school, and it was my Year 2 teacher who probably first made me “love” maths by giving me harder problems to solve than the rest of the class where I had to think more. This primary school also first introduced me to programming – first with logo and the big black “turtle” that moved on the floor and then with BBC BASIC on a BBC Micro and Acorn A3000 – though I didn’t know then that programming and maths would converge an become very important to me. 

Whilst I was at school, I was also lucky enough to have lots of time with my grandmother, who had been a maths teacher (mainly at the Royal College for the Blind) who set me maths problems and sent me coded messages to crack which I always enjoyed. I can also remember doing maths to calm down when I was stressed or apparently hyperactive. 

After having some good KS2 primary teachers I moved to secondary school, where I had a great teacher in Year 7, who again let me do work of my own choice most Friday lessons, including plenty of investigations. I still have a book on the history of Pi that he gave me when he left the school. People are often surprised that I didn’t enjoy the UKMT Junior Maths Challenges when I was at school – I didn’t really understand the benefit of them, and to me at the time they were puzzles that I didn’t really see the point of (I now think this is something that often needs addressing with KS3 students). I admit that I was probably seen as a bit of a geek at school – I once measureddhundred of blades of grass in an effort to determine if the grass around the school was all of the same type. I took my GCSE in Year 10 and then starter A Level Maths in Year 11. For me this was a good idea as it meant I could complete the A Level alongside starting Further Maths in Year 12 – this meant I avoided the problems of needing Year 13 content for Year 12 Further. My A level teacher was fantastic, always willing to help, or discuss things off the course. I appreciated how he always tried to show things from first principles, not just give us a result and then expect us to use it. At the end of Sixth Form I was pretty sure that following a maths degree I wanted to go and do a PhD – my uncle was (and still is) a lecturer in applied mathematics at Durham University – but in Pure mathematics, I was adament I didn’t want to do applied mathematics.

I went to study a 4 year Masters course at the University of Bath, in the end I chose a slightly odd mix of modules. I did a lot of Pure mathematics (group theory, number theory, measure theory etc) and lots of numerical methods, but very little fluids and mathematical modelling. This means I had a slightly odd background to choose (ironically) a PhD in applied mathematics. I had developed a love for the finite element method during some final year numerics modules. Such a simple idea but very powerful and infinitely less frustrating to analyse than finite difference methods with their taylor expansions! I applied to work with Paul Houston at the University of Nottingham, and following a brief meeting In the january of my final year was accepted to study under him and Andrew Cliffe. 

I moved to Nottingham and initially I was meant to be working on anisotropic adaptivity for fluid problems, but about half way through my first year II changed topics and focussed on applying the Discontinuous Galerkin method to the Neutron Transport Equation – this turned out to be significantly harder than we anticipated. A lot of time in my PhD was taken up programming in Fortran. At some point I will probably write about this more…. 

To cut along story short, during my PhD I discovered that I felt more rewarded when I was teaching others – either tutoring undergraduate, lecturing postgraduates from other faculties in statistics or going into schools and running GCSE or A Level revision sessions or doing outreach events – than I did when I was doing my own research. 

Following my PhD I applied for a School Direct place with the University of Nottingham. 

That’s a fairly short run down on how I ended up in teaching. I’d love to hear the stories of other UK based teachers.