You are Here: Home >< Maths

# Edexcel P2 After-test Discusion watch

1. (Original post by RDoh)
For f(x)=|x-1|-2=5x, I think the answer is -3/4.

For the water flow question, I got the cross-sectional area as 43.86m^2 and the volume in a minute as 5260m^3 to 3sf.
I think I got 5260 too - I did 43.86 x 120 = 5263.2 = 5260
2. damn there goes like 4 marks.
3. I did it like this

distance = speed* time
= 2*120
=240, and then times this by the 44, gives 10560, maybe wrong though
4. (Original post by spikeyguru)

..volume of water and couldnt remember volume of a cone so lift out the second part of the integration question.( think it coulda bin done another way but i wanted to get on to the trig asap)

I think that there was a more simple way using the information given about the tangent, but like youself i was eagar to get on to the next question, therefore just guessed it quickly at the end.

The binomial: p = -2 , q = 24

The fg (x) = 1/4 what did people get for this (if i remembered the question correctly)
5. (Original post by sequence123)
I did it like this

distance = speed* time
= 2*120
=240, and then times this by the 44, gives 10560, maybe wrong though
I thought they wanted a volume?
6. Surely volume = distance(ie length) * crossesctional area?
7. I did the speed * 60 * answer to part b
8. For the volumes of revolution question I got

a) π(8/3 - 2ln3) by integration
b) π(2ln3 - 5/3) by working out the volume of revolution of the triangle* and subtracting it from a)

* I did this by realising that it would create a cone of radius 2 and height 2. I didn't know the formula for the volume of a cone but I worked it out (I think) by using the formula for the area of a circle, multiplied by height to get volume of cylinder and divide by 2 to get the volume of the cone. This gave (πr2h)/2 and by subbing in r=2 and h=2, I got 4π.
9. (Original post by sequence123)
I did it like this

distance = speed* time
= 2*120
=240, and then times this by the 44, gives 10560, maybe wrong though
This would have been correct but it looks like you've copied the value of time wrong - it's 60 seconds, not 120 seconds.
10. (Original post by topdude)
does any1 remember what the trig question for tan theta actually was......(so i can work out what i done, and if i got the right answer!)

i think it was...
given that 2sin(theta + 30) = cos (theta+60)
find tantheta

i got -1/(3root3)

stoopidly, i thought you had to find theta, so i did, but didnt get it as an exact figure so i did the WHOLE thing again and got theta=30degrees. then realised i only had to find tantheta, which id just done twice...grrr!
11. I think it went really well.
for the ccross seciton of area i got around 48m 40 soemtihng anyway!
so for volume i got 48x2 m/s
x60 to get the amount per minute

so it is 5760ish

for the volume under the curve i think i got 2ln2+2 2/3pi then the volume under the triangle2 2/3pi took one away from other and got volume of r just to be 2ln2 (might have been 3ln2 now i come ot think of it something ln2 anyway) but i did it a relly long way, first i foudn the equation of the straight line then i squared it, and integrated that times pi, input values. then take away Volume triangle from volume under whole curve! There must be a simpler way to find the volume cut out by the triangel but i just couldnt figure it out.

p=-2 q=24 for binomial

for the trigonemtry qs i manged them all except part ii to find the value of the angle, i relaised afterwards it is a sin^2-sin+c quadratic kinda thing but nevermind

the function quesiton where you ahve to input values and get a sign change didnt really work out for me until right at the end so i may have got that wrong.
and the modulus x-1 find the value of x question didnt work out 100% either
i got -3/4 but when i put it back in it didnt work at all!

added up afterwards think i got around 55-60/75 which is really good for me

fgx=1/4 when x=2

erm my a and b for the graphs were sensible one of them was 2 or -2
thought the log questiosn were really easy, for the change of base rule u end up with ln8/ln5 iirc put in calculator-done, i know my mates struggled with this. the trapezium rule was pretty straight forward but i made a daft mistake with copying numbers which i noticed in time phew.

yep, i am very happy
12. (Original post by Star_inda_sky)

i think it was...
given that 2sin(theta + 30) = cos (theta+60)
find tantheta

i got -1/(3root3)

stoopidly, i thought you had to find theta, so i did, but didnt get it as an exact figure so i did the WHOLE thing again and got theta=30degrees. then realised i only had to find tantheta, which id just done twice...grrr!
I got 1/3root3 no minus sign but its pretty close lol
13. yeh got the same as most of you guys, coundnt do the first trig q and the last mod 1 though. For fg(x) i got 2, and i got 5000 something for the volume but didnt convert to 3 sfg would i lose any marks. I however got something like pie(2ln3 - 4) for the volume of R. 1.29 and 1/6 for the first question. For the 3rd trig i got the values 30, 270 and 150. a = -2 and b=-1. The binomial was q=-2 and p=24
14. (Original post by sequence123)

What did people get for the value whereby f(x) = 5x?
I got -1/3
Yeh, there was only one value for x and it was -1/6 because the question was:

|x-1|-2 = 5x
|x-1| = 5x+2
x-1 = -(5x+2)
-6x = 1
x = -1/6

I thought the paper was pretty easy overall...
15. Can somebody type up the question numbers with however many marks each one was worth?
16. method marks all the baby
17. what was the log questions answers?

first one was lg8/lg5 I think

the integration question wasnt part b just ANS- 2π?
18. (Original post by chats)
what was the log questions answers?

first one was lg8/lg5 I think

the integration question wasnt part b just ANS- 2π?
yea lg8/lg5 or ln8/ln5 dont think it matters. my mate did ans-2pi because she thought the volume under the traingle was just area x pi but i doubted this anyone know the formula for a cone, that would have prob solved it easy peezy lemon squeezy- i hope that ist something that is in the massive data booklet i didnt think to look

bring on s2 and no more maths alevel yay
19. I did this by realising that it would create a cone of radius 2 and height 2. I didn't know the formula for the volume of a cone but I worked it out (I think) by using the formula for the area of a circle, multiplied by height to get volume of cylinder and divide by 2 to get the volume of the cone. This gave (πr2h)/2 and by subbing in r=2 and h=2, I got 4π.
The volume of a cone is 1/3π(r^2)h i think, this gave a volume of 2πln3 for the region R.
yea lg8/lg5 or ln8/ln5 dont think it matters. my mate did ans-2pi because she thought the volume under the traingle was just area x pi but i doubted this anyone know the formula for a cone, that would have prob solved it easy peezy lemon squeezy- i hope that ist something that is in the massive data booklet i didnt think to look

bring on s2 and no more maths alevel yay
I thought it was just 2π (area of triangle * π )

oh well

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: June 21, 2005
The home of Results and Clearing

### 2,072

people online now

### 1,567,000

students helped last year
Today on TSR

### GCSE results day guidance

All you need to know is here

### University open days

1. Bournemouth University
Wed, 22 Aug '18
2. University of Buckingham
Thu, 23 Aug '18
3. University of Glasgow
Tue, 28 Aug '18
Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams