Edexcel Maths C1/C2 2007

Competition - post a photo you've taken of nature >>

Scroll to see replies

I got same answers deathawaitsu, but Q8 was not on C2 (I did soil myself for a second though).

1) Definite Integration
2) Factor theorem stuff
3) Binomial
4) Cosine etc
5) Trap rule etc
6) Logs
7) Circle geometry
8) Geometric series
9) Sin graph/trig
10) Differentiation

edit: and I agree with your answers.

I assume that Q was from C1.

Reply 21

Asian89

o crap, 10 marks for Q11 on C1. how much is that going to cost me :frown:

btw if you retake with edexcel and get lower, which mark do you keep. i assumed your retake would be your final mark but i heard that your highest mark from any paper is counted? any confirmation?

Reply 22

Swayum

Ok I've changed the order to like you think it was and I've removed the C1 question.

I need to know the answer to this question though:

Last question on the C1 paper. Find the area of the triangle APB or something. A and B had y coordinate 1. So I did:

Area = 1/2 * base * height
= 1/2 * AB * (vertical_distance_between_P_and_y=1)

The vertical distance I got as 10/3 - 1. I can't remember length AB but it wasn't a very nice number.

Is this right or not?

*Edit*

To the guy above, you do keep your highest mark. Even if you sit the paper 4 times.

Reply 23

shiny_89

[QUOTE="DeathAwaitsU"]Ok, I got bored of waiting for the whole Edexcel rules thing so I'm going to post my take on the C2 exam. I'd like to stress that my answers aren't necessarily correct and I'm doing this all from memory after 12 hours so I may have forgotten the questions and so I might be posting complete crap. If you do get something different (and you think you're right) please let me know. I can't remember 1 question in the paper though which is annoying and the questions aren't in the correct order at all:

But here it is:

1) The definite integration question.

You had to find the integral giving your answer in the form

a + b\sqrt{2}

\int^8_1 (1/\sqrt{x}) \, \mathrm{d}x = -2 + 4\sqrt{2}

2) The polynomial question with the factor theorem.

a) They gave you some function and wanted you to find the remainder when you divided it by (x-2) I think. So all you had to do was:

f(2) = -16

b) They told you (x+2) is a factor of the function and wanted you to hence show that the function factorises like

(x+2)(3x-2)(linear)

I would show how it's done but I don't remember the function well. I'm not entirely sure whether the factor was (x-2) or (x+2).

3) The binomial expansion question.

a) Find the first four terms of

(1+kx)^6

.

I used the

1 + nx + \frac{n(n-1)x^2}{2!}...

formula to give:

1 + 6kx + 15k^2x^2 + 20k^3x^3

b) They told you the coefficient of x is the same as the coefficient of x^2. So:

6k = 15k^2

15k^2 - 6k = 0

k(15k - 6) = 0

k = 6/15 (k>0)

I actually really do not remember getting 6/15 at all but it seems right now. I could have the question wrong.

c) Find the coefficient of x^3 which was just plugging in k into

20k^3

.

4) The question with the triangle + cosine rule.

a) They gave you a triangle with sides 4cm, 5cm, 6cm and an angle A between 5cm and 6cm. They asked you to show that cos A=3/4:

cos A = \frac{b^2 + c^2 - a^2}{2bc}

cos A = \frac{6^2 + 5^2 - 4^2}{2*5*6}

cos A = 3/4

b) Hence or otherwise, find the exact value of sin A.

In a right angled triangle, cos A = adjacent/hypoteneuse and sin A = opposite/hypoteneuse. So draw a right angled triangle, with the hypoteneuse as 4 and the adjacent as 3. Then the opposite can be worked out as:

a^2 + b^2 = c^2 (Pythagoras' theorem)

3^2 + b^2 = 4^2

b = \sqrt{7}

sin A = opposite/hypoteneuse

sin A = \sqrt{7}/4

5) The trapezium rule question.

a) Fill out the y values on the table. The x values on the table were 0, 0.5, 1, 1.5 and 2.

b) You were asked to work out an approximation for

\int^2_0 (x\sqrt{x^3 + 1}) \, \mathrm{d}x

Using the trapezium rule:

A = \frac{0.5}{2}(0 + 6 + 2(0.53 + 1.414 + 3.137)) = 4.04 (3 s.f)

c) They showed you a graph with a line going through the origin and the point (2,6). They also made it clear that the curve goes through the origin and the point (2,6) as well. Find the area between the line and curve, labelled R.

You had to realise that the area under the line was a triangle whose area you could work out doing:

Area = 1/2 * base * height = 1/2 * 2 * 6 = 6

This is because between the origin and the point (2,6) the x distance is 2, so the base is 2. And between the origin and the point (2,6), the y distance is 6, so the height was 6.

The area under the curve you worked out in part b as 4.04.

So the area of R was:

R = Area of line - area of curve = 6 - 4.04 = 1.96 (3 s.f)

6) The logarithms questions.

a) 8^x = 0.8

x = \frac{\mathrm{log}0.8}{\mathrm{log}8} = -0.107

b) Don't remember the logarithm well but x = 21 was the answer.

7) The circle question./b]

a) Working out the equation of line through M and some point was just y - b = m(x-a) and where m was dy/dx of the two points they gave you.

By a circle theorem, the equation of the line you worked out before was perpendicular to the equation of the line you're trying to work out in part a. Then it was just y - b = -1/m (x-a) (using the coordinates of the point M).

b) If the x coordinate of the centre is 6 (which they told you), you could work out its y coordinate using your answer in part a. I believe it was -1. So the point P, the centre, was (6,-1).

Equation of the circle is then:

(x-a)^2 + (y-b)^2 = r^2

(x-6)^2 + (y+1)^2 = r^2

To work out the radius, you had the centre and a point on the circle. The distance between these points is then equal to the radius. Working it out gave r^2 = 26

So the equation was:

(x-6)^2 + (y+1)^2 = 26

8) The geometric series question.

a) They said that profit in 2006 was £50,000 and they expected it to multiply by r every year. Find the general term for the profit.

Profit = 50000r^(n-1)

b) They said that they expect the profit to exceed £200,000 in Year n. Show that

n > \frac{\mathrm{log}4}{\mathrm{log}r} + 1

You had an expression for the profit and you were told it's greater than £200,000. So:

50000r^{n-1} > 200000

r^{n-1} > 4

n-1 > \frac{\mathrm{log}4}{\mathrm{log}r}

n > \frac{\mathrm{log}4}{\mathrm{log}r} + 1

c) They told you r = 1.09. They asked you to work out when the first profit exceeds £200,000.

n > \frac{\mathrm{log}4}{\mathrm{log}1.09} + 1

n > 17.086...

n must be GREATER than 17.086, so n must be 18.

9) The question where you had to sketch y = sin(x + pi/6).

I'm going to talk in degrees for a minute here.

a) Well for the sketch, I started my graph at (0,0.5) and sketched it down to (150,0) and then brought it back up to (360,0.5).

b) The points of intersection were:

(0,0.5), (\pi - \pi/6, 0) and (2\pi - \pi/6, 0)

c) Solve the equation sin(x + \pi/6) = 0.65

Let x + \pi/6 = A

sin A = 0.65
A = 0.708, 2.434

x + \pi/6 = A

x = A - \pi/6

x = 1.91, 0.18 (2dcp)

10) The question with the cuboid.

They gave you a cuboid with sides 2x, x and y. They told you the surface area of the cuboid is equal to 600.

a) Show that the

V = 200x - \frac{4x^3}{3}

(V being the volume).

First start by working out the area of each of the face of the cuboid. You know they add up to 600. On a cuboid, faces opposite each other have the same area. There were 3 different faces on the cuboid.

Area of the first face = 2x * x = 2x^2
Area of the second face = 2x * y = 2xy
Area of the third face = x * y = xy

Each face appears twice on the cuboid, so the total surface area can be worked out like:

A = (2* 2x^2) + (2 * 2xy) + (2 * xy)

600 = 4x^2 + 4xy + 2xy

600 = 4x^2 + 6xy

600 - 4x^2 = 6xy

\frac{600 - 4x^2}{6x} = y

Ok so now we have y in terms of x.

Volume = length * base * height

V = 2x * x * y = 2x^2y

V = 2x^2 * (\frac{600 - 4x^2}{6x})

With a bit of algebra, you can show that:

V = 200x - \frac{4x^3}{3}

b) Find the maximum volume of the cuboid.

\frac{\mathrm{d}}{\mathrm{d}x} V = 200 - 4x^2

The maximum occurs at a turning point, which means dV/dx = 0, so solve that equation:

200 - 4x^2 = 0

x^2 = 50

x = \sqrt{50} (-\sqrt{50}

is invalid)

V = 200 * \sqrt{50} - \frac{4*\sqrt{50}^3}{3}

V = 942 cm^3

c) Make sure it's a maximum turning point.

The second differential = -8x

-8 * \sqrt{50}

is negative, so it is a maximum turning point.

*Edit2*

Ok edited to remove the C1 question which was scaring everyone =P.

The order has been revised as well.

GUYS.. for question 8, geometric series, didnt they say to find the year??? soo, was it 18th year or year 2023(Year 18)???

Reply 24

lil one

I have done so appalingly, I actually cannot stop crying.

Reply 25

nota bene

DeathAwaitsU

Last question on the C1 paper. Find the area of the triangle APB or something. A and B had y coordinate 1. So I did:

Area = 1/2 * base * height
= 1/2 * AB * (vertical_distance_between_P_and_y=1)

Ok, as you know I've not taken the exam :tongue:

. However this definitely looks like a sound method :smile:

Reply 26

Kill.Me.Now

DeathAwaitsU

yeh i got some horrible fraction for that answer as well, i think i worked out something like 147/50something.

someone tell me they got that as well :confused:

Reply 27

foxygreg

for the geometric series question it said find the year it first exceeded 200,000 now as they had the things in brackets (year 1) etc i'm sure either should be acceptable i wrote both cos i hate these ambiguous questions on what form to leave it in. I agree with all the answers i thought the paper was good on every question, basically, you could check whether you had got your answers right.

Reply 28

Swayum

OH MAN I JUST REALISED I'M AN IDIOT (well no, I actually realised this when I did my maths GCSE in pencil).

Last part of the geometric series question, what did everyone get as their answers (I forgot to put it in before in my post)? I thought it was £80,000 but it OBVIOUSLY wasn't since the profit by Year 2 is clearly going to be greater than £100,000 and so by Year 10 it's not going to be £80,000. I misread my calculator...ARRRRGGGGGHHHHHH. But 3 other people I spoke to said similar stuff to me so maybe I'm remember the question incorrectly.

Reply 29

Kill.Me.Now

^^^for that one i think i got something like £700,000something, and they wanted the answer to the nearest thousand.

Reply 30

downuno

When is an official .PDF file of the May 2007 Past paper going to surface this forum?

Reply 31

maxhk

DeathAwaitsU

Haha..

I am so used to doing exams with pencil too.

Reply 32

intek7

does any 1 remember the c1 questions n ans?:s

Reply 33

Swayum

On a side note, does anyone know if the rumour that you need to get 75/75 raw in maths to get 100/100 UMS true? I remember for spanish GCSE we were told getting 57/60 would mean we get 100% UMS. But I think I also heard you actually need to get 100% in maths to get 100% on UMS as well.

Reply 34

Kreuzuerk

I pretty confident that it was the 17th year because the question asked in which year it would exceed the value and there has been similar questions on past papers which required the year that it would exceed, not the next year.

Reply 35

TheTallOne

Q8 did appear in the C2 exam.
I made a mistake - didn't take logs to base 10 on both sides, so I ended up with:
4/log1.09+1=107....

I think I may have lost 2 marks or so..

Reply 36

TheTallOne

DeathAwaitsU

More or less, you might get 74/75 and still get 100 UMS, but generally the 100 UMS is very high.

Reply 37

ob.is.a.bit.good

Asian89

o crap, 10 marks for Q11 on C1. how much is that going to cost me :frown:

btw if you retake with edexcel and get lower, which mark do you keep. i assumed your retake would be your final mark but i heard that your highest mark from any paper is counted? any confirmation?

they give you the higher mark

Reply 38

ob.is.a.bit.good

Kill.Me.Now

yeh i got some horrible fraction for that answer as well, i think i worked out something like 147/50something.

someone tell me they got that as well :confused:

i also got something similar :smile:

im sure we'll get the method marks for this q :biggrin:

Reply 39

Hingie

moreiniho

I thought about that question a lot and ended up putting the 17th year too, because of the sopecific the wording of 'in which year does the profit exceed £20,000'. However, having agonised over it some more I think I'm going to have to agree with my friends who all put the 18th year - the model calculates the predicted profits for the entire year, not just the start... but what you said about similar questions on past papers does inspire me with some confidence!