C2 June 2012

CCEA C2 June 2012 answers:

1i. (3,-2)
1ii. -3/4
1iii. 3y = 4x + 7

2a)i. 104 degrees
2a)ii. 290 cm^2
2b)i. 54 cm^2
2b)ii. 33 cm

3i. http://www.wolframalpha.com./input/?i=y+%3D+cos2x
3ii. pi = 180 degrees
3iii. pi/6 , 5pi/6 , 7pi/6 , 11pi/6

4a. 1 + 2x + 1.8x^2 + 0.96x^3
4b. i.
Year 1: 900
Year 2: 820
Year 3: 756
4bii. un+1 = 0.8un + 100
4biii. limit = 500

5i. a = 5, b = 3
5ii. 6.5m
5iii. 07:24

6a. 2.5x^2 + 0.75x^(4/3) + 7x + c
6b. 2 units^2

7a. 1.5 or -1.5
7b. r=0.8

8i. http://www.rapidtables.com/math/algebra/logarithm/Logarithm_Base_Change.htm

8ii. x = 4 or 16

If there is any mistakes please shout :smile:

Scroll to see replies

Reply 1

Crooked fingers

For gods sake lost about 15 marks

Reply 2

richard1123

I did the most stupidest things on this paper.

1. Drew the cos2x graph completely fine.
.... but what did I decide to do, say the period was 3pi/4 :O.
I just looked at my graph wrong! :frown:

[-1 mark]

2. H = a + bsin(30*t)
for 0500 = 5hrs
a = 5, b = 3

H = 5 + 3sin(150)
My brain processes 5 + 1.5 as 7.5 :/ [-1 mark]

3. got the x to = sqrt(32) or 4sqrt(2) like come on.

log_4x + log_x16 = 3
log_4(5.7) + log_(5.7)16 = (1.3) + (1.6) = 2.9 I was CLOSE fgs! :/ [-6 marks] AND TO BE FAIR CCEA YOU DIDNT SAY THE EXPRESSION WAS EXACTLY EQUAL TO. :wink:

Is the +- 1.5 right!?!? I got that people said to me it was 1.22 or something?

(edited 11 years ago)

Reply 3

Micky76

Original post by richard1123

I did the most stupidest things on this paper.

1. Drew the cos2x graph completely fine.
.... but what did I decide to do, say the period was 3pi/4 :O.
I just looked at my graph wrong! :frown:

Is the +- 1.5 right!?!? I got that people said to me it was 1.22 or something?

Yes +- 1.5 is right. Try substituting 1.22 to find a. Then substitute a and r into your equations. You won't get 560 or 1260. Have a look at my post here for solution:

http://www.thestudentroom.co.uk/showthread.php?t=2023239&page=3&p=37988866#post37988866

Reply 4

Micky76

Original post by richard1123

I did the most stupidest things on this paper.

1. Drew the cos2x graph completely fine.
.... but what did I decide to do, say the period was 3pi/4 :O.
I just looked at my graph wrong! :frown:

Is the +- 1.5 right!?!? I got that people said to me it was 1.22 or something?

Sorry you will get it to equal one of them but not the other.

Reply 5

MissMedic

For the time after midnight one I got 22:40 because I worked it to be -1 and a third hours which I took to be away from 24 hours... :/ I don't even know how to get a different answer!

Reply 6

richard1123

oh and also the limit question I got 10,125 it was never that big to start with... I just gave up on that one, we were never taught recurence relations. I got 0.9111111111 for that one, as I thought it was something to do with recurring decimals lol

Reply 7

Micky76

Original post by MissMedic

For the time after midnight one I got 22:40 because I worked it to be -1 and a third hours which I took to be away from 24 hours... :/ I don't even know how to get a different answer!

H = 3 = 5 + 3sin(30t)
>3sin(30t) = -2
>sin(30t) = -2/3
>sin^-1(-2/3) = 221.81 = 30t
t = 7.3936 => 07:24

Reply 8

Micky76

Original post by richard1123

Yeah, the limits thing is not common. CCEA is getting more tough as they are starting to give questions that are worded in a fancy way and they touch on things that are not most commonly taught. I suspect that when I repeat it in Jan 2013 it will be even harder.

Reply 9

richard1123

Would I get any method marks for my log_4x question?

Reply 10

richard1123

If I worked it out exactly the way I should have, only, when I came to multiply by log_4x I forgot to move the log_4x over with the 3. I did the change of base on it fine, trying to find more marks.

Reply 11

richard1123

Original post by Micky76

Sorry you will get it to equal one of them but not the other.

I'm confused is +- 1.5 wrong now?

Reply 12

richard1123

Original post by MissMedic

For the time after midnight one I got 22:40 because I worked it to be -1 and a third hours which I took to be away from 24 hours... :/ I don't even know how to get a different answer!

it said after midnight. :L

Reply 13

Micky76

Original post by richard1123

If I worked it out exactly the way I should have, only, when I came to multiply by log_4x I forgot to move the log_4x over with the 3. I did the change of base on it fine, trying to find more marks.

Please reply to with quote so that I know when you reply. You should get about two marks for change of base.

Reply 14

String.

Original post by Micky76

Did you get all them? :redface:

This was posted from The Student Room's Android App on my HTC Wildfire S A510e

Reply 15

Micky76

Original post by richard1123

I'm confused is +- 1.5 wrong now?

+- 1.5 is right

Reply 16

richard1123

Original post by Micky76

Please reply to with quote so that I know when you reply. You should get about two marks for change of base.

I get confused with this, only started using it a while back lol. Is that better.

Was wondering why people weren't replying. haha :tongue:

Reply 17

Micky76

Original post by String.

Did you get all them? :redface:

This was posted from The Student Room's Android App on my HTC Wildfire S A510e

I got ~ 66/75 which is crap. I forgot the change of base log proof as I didn't revise it because it didn't say that it was required on the specification. I also got the wrong angle for 5iii. Might have also lost a mark for integrating the area for 6b. between negative limits and thus getting a negative area.

Reply 18

larryj

I can I just say that this isnt helping anyone and to post "answers" it is against forum rules. this makes people panic. DO NOT POST ANSWERS ON THE SAME DAY OF THE EXAM! it says quite clear!