** Higher Level Maths Paper 1 2012 Before/After **

Dazaq

im reasonably happy,but didnt get 3c(ii),6c(ii),and i seem to have got the correct answer for integration but dat cant be right cause i was subbing in a's for x's like dere was no tomorrow,very lucky with q5 cause i did dat exact induction dis morning and did a similar binomial aswell,could be a whole lot worse!!!

Dazaq

ashh wrote: »

Is it possible for α(squared) + β(squared) in q2 (b) (i) to be negative?... Or is there some complex root trickery afoot?...

i got -6

SellingJuan

ashh wrote: »

Is it possible for α(squared) + β(squared) in q2 (b) (i) to be negative?... Or is there some complex root trickery afoot?...

Yea its -6

Frankjones45

Can someone please answer this?

I did Q6 part c (i) out correctly,had second thoughts about it and put a line through it(lightly) ad did it out again but a different method and wrong...Do i still get marks?

Wesc.

Dicksboro_man wrote: »

got different ans for those:

1bii = x^3-5x^2+2x+8

4a b=4ac/(a+c)

4bi root(n+1) - 1


could be wrong though also i didnt really try 8c and messed up 6 ciii but ah well..

Hold up I got this guys answers here too.

Dicksboro_man

Wesc. wrote: »

Hold up I got this guys answers here too.

as in mine or the other guys?

montown

Tankosaur wrote: »

1// (a) a=3 b=-2 c=5
(b)(i) -2,1,3
(ii) x^3 + x^2 -6x =0
(c) was a proof.
(ii) t is a negative number

2// (a) x=3
(b) (i) -6
(ii) 5x^2+-12x+20
(c) proofs

3// proof
(b)(ii) y=-1 x=3
(c) + and - (root3/2 + i/2)
k=1

4// 2ac/c+4 =b
(b) (i) proof
(ii) root n =1 - root n
(ii) 9
(c) proof

5// (a) x=5
(b) (i) 10C r-1 3^11-r 2^1-r x^23-3r
(ii)76545/8
(ii) 23/3 is not rational therefore 23-3r does not = 0
(c) both (i) and (ii) are proofs

6//24x(4x^2)^2
(ii)2/root(9-4x^2)
(b) (i) proof
(ii)6y=x+9
(c)8+4cos4x + 8cos2x
4cos^2 2x + 8cos2x + 8
(2cos2x + 2)^2 >0 thefore all values of fx are increasing

7// proof dy/dx =-1/3
(b) dy/dx = 2y-2x / 4 + 6y -2x
same slopes i.e. m=1/2
(c) different signs for f(1) AND f(0)
3/4 and 1/2
the approximations are repeating

8// x + sin2x / 2 + e^3x /3 + c
(b) 4ln7
(ii) pi/16 - 1/8
(c) a = root k
(ii) area is 5/3 x k^3/2

is that definitely right for the coefficient of x^8? i got something much more regular than 76545/8

Tankosaur

Dicksboro_man wrote: »

got different ans for those:

4a b=4ac/(a+c)

4bi root(n+1) - 1


could be wrong though also i didnt really try 8c and messed up 6 ciii but ah well..

Sorry, those are correct as far as I know.

I must have misread when I was typing up

Edit: actually I think 2ac/a+c is still correct

For arithmetic : 2x middle term = 1sr term + 3rd term

so 2/b = 1/a + 1/c
Rhs= c+a/ac
cross multiply to get b = 2ac/(a+c)

Tankosaur

montown wrote: »

is that definitely right for the coefficient of x^8? i got something much more regular than 76545/8

I've seen others post that answer, then again others posted different ones too.

Epsi

(ii) pi/16 - 1/8

Awesome!

ray giraffe

Tankosaur wrote: »

1// (a) a=3 b=-2 c=5
(b)(i) -2,1,3
(ii) x^3 + x^2 -6x =0
(c) was a proof.
(ii) t is a negative number and t not equal to -1 (t=-1 gives 2 equal roots which you don't want!)

2// (a) x=3
(b) (i) -6
(ii) 5x^2+-12x+20
(c) proofs

3// proof
(b)(ii) y=-1 x=3
(c) + and - (root3/2 + i/2)
k=1

4// 2ac/c+4 =b
(b) (i) proof
(ii) root n =1 - root n
(ii) 9
(c) proof

5// (a) x=5
(b) (i) 10C r-1 3^11-r 2^1-r x^23-3r
(ii)76545/8
(ii) 23/3 is not rational therefore 23-3r does not = 0
(c) both (i) and (ii) are proofs

6//24x(4x^2)^2
(ii)2/root(9-4x^2)
(b) (i) proof
(ii)6y=x+9
(c)8+4cos4x + 8cos2x
4cos^2 2x + 8cos2x + 8
(2cos2x + 2)^2 >0 thefore all values of fx are increasing

7// proof dy/dx =-1/3
(b) dy/dx = 2y-2x / 4 + 6y -2x
same slopes i.e. m=1/2
(c) different signs for f(1) AND f(0)
3/4 and 1/2
the approximations are repeating

8// x + sin2x / 2 + e^3x /3 + c
(b) 4ln7
(ii) pi/16 - 1/8
(c) a = root k
(ii) area is 5/3 x k^3/2

Source: I'm a maths teacher!

ashh

Dazaq wrote: »

i got -6

That's what I got, but I freaked in the exam 'cause a squared number is always positive?...

Tankosaur

Epsi wrote: »

Awesome!

Virtual high five !!

Tankosaur

ray giraffe wrote: »

Source: I'm a maths teacher!

Balls, well at least I'll get most of the marks

is everything else more or less right though mr maths teacher man?

emmamurphy233

ashh wrote: »

Is it possible for α(squared) + β(squared) in q2 (b) (i) to be negative?... Or is there some complex root trickery afoot?...

It was -6 I'm fairly sure.

ray giraffe

Tankosaur wrote: »

Balls, well at least I'll get most of the marks

is everything else more or less right though mr maths teacher man?

Typo in your answer for Q6: 24x(4x^2-1)^2 !

Dazaq

am i de only one who didnt get a decimal in my binomial expansion

Epsi

Tankosaur wrote: »

Virtual high five !!

Back at ya! Thought I made a mistake when I got that answer during the exam. Nice to see other people get it as well.

Togepi

I'm sure you've all seen the paper online but I'm too lazy to look through the thread. :P It's here anyway for anyone who hasn't seen it.

Tankosaur

Epsi wrote: »

Back at ya! Thought I made a mistake when I got that answer during the exam. Nice to see other people get it as well.

Most People I talked to didn't divide by the differential of 2x.

Tankosaur

ray giraffe wrote: »

Typo in your answer for Q6: 24x(4x^2-1)^2 !

gracias por favor.

Corrected the error there. Had the answer right anyway.


Just glad I've finally done a decent exam :P

Cruel Sun

came in here by accident, thought it was the ordinary paper thread, got fairly worried there for a second when I seen the stuff ye were writing.

kyle84

I got most answers that the guy who posted his exam got. I was annoyed overall though. I went in aiming and expecting 100 %. i needed it because our teacher didn't teach us paper 2. But i think after seeing some of those answers i got an A1. I guessed the k=1 after messing up the first part (switched the coefficients). I think with attempt marks I'll settle in around 275-280

JailB8 xoxo

kyle84 wrote: »

I got most answers that the guy who posted his exam got. I was annoyed overall though. I went in aiming and expecting 100 %. i needed it because our teacher didn't teach us paper 2. But i think after seeing some of those answers i got an A1. I guessed the k=1 after messing up the first part (switched the coefficients). I think with attempt marks I'll settle in around 275-280

man you must have been so annoyed dropping those 25 marks

cocopopsxx

montown wrote: »

is that definitely right for the coefficient of x^8? i got something much more regular than 76545/8

Do you mind me asking what you got? I got something much more regular than 76545/8 too

Mista

cocopopsxx wrote: »

Do you mind me asking what you got? I got something much more regular than 76545/8 too

I got 1260 (i think)

Wanchor

cocopopsxx wrote: »

Do you mind me asking what you got? I got something much more regular than 76545/8 too

Noooo! I didn't write it down because it was so ridiculous!

cocopopsxx

Mista wrote: »

I got 1260 (i think)

That could be right...one of my friends got the exact same. Damn, I messed up such a nice question

Wanchor wrote: »

Noooo! I didn't write it down because it was so ridiculous!

Really? So annoyed that I messed up such a nice question- was almost sure I got it right. Urghhh!

kyle84

Yes,yes i was

Wesc.

cocopopsxx wrote: »

Do you mind me asking what you got? I got something much more regular than 76545/8 too

I got that too. Almost certain it's correct.