Maths HL P 1 - aftermath

**Timbuk2**

Deleted User wrote: »

I went with 'otherwise' and proved it by induction.

That's sheer genius

karen-xxxxx

Did anyone get
b = 4
c = -7
and d = - 10
for Question 1, part c?

kieran--f

karen-xxxxx wrote: »

Did anyone get
b = 4
c = -7
and d = - 10
for Question 1, part c?

no got -11/4 -7/2 and 1/4 haha surely wrong

karen-xxxxx

kieran--f wrote: »

no got -11/4 -7/2 and 1/4 haha surely wrong

awh man, i'm probably wrong. Ohwell a lovely paper otherwise

**Timbuk2**

karen-xxxxx wrote: »

Did anyone get
b = 4
c = -7
and d = - 10
for Question 1, part c?

I got those answers!

Indigo Sunrise

Did anyone else forget to put in the make of their calculator?
what happens if you don't?

karen-xxxxx

**Timbuk2** wrote: »

I got those answers!

Oh great, I filled in x for two and x for minus one after words and they worked out as factors so i hoped it was right.

Trackmedown

did anyone else get like really weird looking decimals in the complex number question (part c)?

thought the paper was alritish accept 4 that curve thingy... took a wild guess and said asymatope (i no i cant even spell it!) lol

karen-xxxxx

Trackmedown wrote: »

did anyone else get like really weird looking decimals in the complex number question (part c)?

thought the paper was alritish accept 4 that curve thingy... took a wild guess and said asymatope (i no i cant even spell it!) lol

Ya they were decimals, but when you used one for w, if the i's cancelled ( showing it was real) then they were probably right

CantStandMeNow

Trackmedown wrote: »

did anyone else get like really weird looking decimals in the complex number question (part c)?

thought the paper was alritish accept 4 that curve thingy... took a wild guess and said asymatope (i no i cant even spell it!) lol

Yup we were supposed to leave it in polar form.. I did the same thing.. we just went one step too far.. i dunno if they can take marks off for that because technically we just went too far but its still right?

eoins23456

got those answers as well but then realised they werent in arithmetic order.but then got the answer that were posted by ur man

citizenerased1

mark.oc wrote: »

Q.1 (a) k = -3, t = 9

(c)(i) -3-b
(ii) -2-2b
(iii) b = -4, c = 1, d = 6

Q.2 (a) x = 3, y = -2, z = -1

(b)(i) 4
(ii) rt20 or 2rt5

Q.3 (a) x = 4, y = 2

(b)(i) ±6
(ii) -8

(c) Didn't take them down as they were all decimals.

Q.4 (a) 47/99

(b)(i) a = -42, d = 6
(ii) 0

(c)(iii) 27230

Q.5 (a) x = 2

(c)(ii) 47

Q.6 (a) x = 4/3

(b)(i) 2/5
(ii) line

(c)(i) [LATEX](-4-2xy^3)/(2+3x^2y^2)[/LATEX]
(ii) 2x + y - 6 is the tangent.

Q.7 (b)(i) 2/(1-2cosxsinx)

(c)(ii) minimum

Q.8 (a) -(cos2x)/2 + (e^4x)/4 + c

(b) 37 units

(c)(i) ln((1+sinb)/(1+sina))
(ii) ln((1+cosa)/(1+cosb))

Q.7 (b)(i) 2/(1-2cosxsinx) ya suree? i got 2/(cosx - sinx)^2 it works out in the next part perfectly too...
got 27 units for area
and the square root of 16P^2 + 1 for 1(B)

1 and 2 were grand
and im a highly average student normally :P
SCOREEEEE

CantStandMeNow

citizenerased1 wrote: »

Q.7 (b)(i) 2/(1-2cosxsinx) ya suree? i got 2/(cosx - sinx)^2 it works out in the next part perfectly too...
got 27 units for area
and the square root of 16P^2 + 1 for 1(B)

1 and 2 were grand
and im a highly average student normally :P
SCOREEEEE

I got 2/(1-2cosxsinx) aswell.. it worked out perfectly in the next part too

The proof of the p thing in Q1 was 16p^2 > -1 right? Makes sense anyway.

eoins23456

citizenerased1 wrote: »

Q.7 (b)(i) 2/(1-2cosxsinx) ya suree? i got 2/(cosx - sinx)^2 it works out in the next part perfectly too...
got 27 units for area
and the square root of 16P^2 + 1 for 1(B)

1 and 2 were grand
and im a highly average student normally :P
SCOREEEEE

the 1-2cosxsinx in the same thing as (cosx -sinx) squared:)

NumberZeroNine

citizenerased1 wrote: »

Q.7 (b)(i) 2/(1-2cosxsinx) ya suree? i got 2/(cosx - sinx)^2 it works out in the next part perfectly too...
got 27 units for area
and the square root of 16P^2 + 1 for 1(B)

1 and 2 were grand
and im a highly average student normally :P
SCOREEEEE

I got 27 too, posted a reply on page 10 or 11 asking how it would be marked, did you make the same mistake (I have the details in that post)?

Ruski

That paper was absolutely tasty. I did all 8 questions with another half an hour to spare. The only thing that caught me out was question 2 (b) and maybe the past c of question 7 but that's just about it. Question 4 part C threw me off as well. I couldn't remember anything for that stuff.

karen-xxxxx

NumberZeroNine wrote: »

I got 27 too, posted a reply on page 10 or 11 asking how it would be marked, did you make the same mistake (I have the details in that post)?

The area is 37, because the -32 changes to positive because it is on the opposite side of the x axis to the five.

CantStandMeNow

karen-xxxxx wrote: »

The area is 37, because the -32 changes to positive because it is on the opposite side of the x axis to the five.

It was 37, our teacher did it out after!

Edit: Oh sorry just saw it wrong haha

DancingQueen:)

I got 153 for the area At first I did it by differentiation and realised about 5 minutes before the end and changed it all. I was obviously wrong but pretty sure I got the method right (the second time) so hopefully I won't lose too many marks.

Reillyman

For 8.(C)(iii) did everyone use the [latex]
sin(pi-a)=cosa[/latex] and [latex]cos(pi-b)=sinb[/latex] ?

EuropeanSon

Reillyman wrote: »

For 8.(C)(iii) did everyone use the [latex]
sin(pi-a)=cosa[/latex] and [latex]cos(pi-b)=sinb[/latex] ?

Surely you mean sin(pi/2 -b)=cos(b)?

NumberZeroNine

Reillyman wrote: »

For 8.(C)(iii) did everyone use the [latex]
sin(pi-a)=cosa[/latex] and [latex]cos(pi-b)=sinb[/latex] ?

I let b = pi/2 - a

And then solved it using the compound angle formulae. Sin90 and Cos90 nicely chopping it down when multiplied.
I'm not saying that your way wouldn't work but I was working on proofs on wednesday and they just came to mind straight away.

Angles of (90 [which is pi/2] - A) change the function ie sin(90-A)= cosA

DGRulz

Im very unsure about this paper. I thought it was hard when I walked out but looking at it now it seems easier. got 127 for the area but forgot to right units and got 8 for 3bii and just realised i did out 6 roots for ci :S. I knew how to do 2bii but couldnt remember the order of things. TBH i was so drained that by the time I got to 1 and 2. Despite the fact i knew how to do it I couldnt do 1c . For 2ci i brought the ab across and reduced it to (a-b)squared and the left a note saying that because anything squared is greater then 0 it was correct. doubt ill get the marks though.

I hope they don't castrate us w/ Paper 2 to balance it out.

SantryRed

What is the answer to Q1(b)?

Is 16p^2 +1>0 correct?

As that's a ture statement which proves the roots are real?

EuropeanSon

SantryRed wrote: »

What is the answer to Q1(b)?

Is 16p^2 +1>0 correct?

As that's a ture statement which proves the roots are real?

Yes.

zam

SantryRed wrote: »

What is the answer to Q1(b)?

Is 16p^2 +1>0 correct?

As that's a ture statement which proves the roots are real?

Well I said 16p^2 > -1
But I'm sure your answer merits the bulk of the marks!

SantryRed

SantryRed wrote: »

What is the answer to Q1(b)?

Is 16p^2 +1>0 correct?

As that's a ture statement which proves the roots are real?

Yeah, as far as I can see because p is squared it will always be greater than 0 (or -1 if you moved that over like me).

EuropeanSon

zam wrote: »

Well I said 16p^2 > -1
But I'm sure your answer merits the bulk of the marks!

It merits all of them. It's the exact same answer as yours. A true statement is a true statement, and that's all that's needed. I said 1>0 and 16p^2>=0 too, but that was just overkill on my part.

XXRachelXX

DGRulz wrote: »

Im very unsure about this paper. I thought it was hard when I walked out but looking at it now it seems easier. got 127 for the area but forgot to right units and got 8 for 3bii and just realised i did out 6 roots for ci :S. I knew how to do 2bii but couldnt remember the order of things. TBH i was so drained that by the time I got to 1 and 2. Despite the fact i knew how to do it I couldnt do 1c . For 2ci i brought the ab across and reduced it to (a-b)squared and the left a note saying that because anything squared is greater then 0 it was correct. doubt ill get the marks though.

I hope they don't castrate us w/ Paper 2 to balance it out.

Thats what I did what were you meant to do ? Also if you get the answer in a question but don't realise it and keep going do you still gut full marks ?

CantStandMeNow

XXRachelXX wrote: »

Thats what I did what were you meant to do ? Also if you get the answer in a question but don't realise it and keep going do you still gut full marks ?

Yeah it's right! Ridiculously simple for a (c) part.. same with (c)(ii).. eh i'm not sure really they might take off 3 maximum it depends on the question! I'm terrified for paper 2.. it has to be so hard or else there's going to be sooo many A's

RedRebel92

XXRachelXX wrote: »

Thats what I did what were you meant to do ? Also if you get the answer in a question but don't realise it and keep going do you still gut full marks ?

ya, thats right!!

Victoria.

I stupidly forgot to put down the make and model of my calculator
Was so stressed. Just opened the paper. Does anyone know if it is a problem?

Making It Bad

Part 7(c) look really easy except I couldn't get it out! Got it to be "loge(1+x)" when differentiated except this didn't equal 0 when you substitute in for x it equalled "-1" where the hell did I go wrong?

XXRachelXX

CantStandMeNow wrote: »

Yeah it's right! Ridiculously simple for a (c) part.. same with (c)(ii).. eh i'm not sure really they might take off 3 maximum it depends on the question! I'm terrified for paper 2.. it has to be so hard or else there's going to be sooo many A's

It was for the 16p^2 one, I has at one stage 16p^2-1>0 but then I broke it up into (4p+1)(4p-1) for some crazy reason, how many marks would you say I'd lose ?

EuropeanSon

XXRachelXX wrote: »

It was for the 16p^2 one, I has at one stage 16p^2-1>0 but then I broke it up into (4p+1)(4p-1) for some crazy reason, how many marks would you say I'd lose ?

That's wrong. It was 16p^2 + 1 > 0

almostnever

Victoria. wrote: »

I stupidly forgot to put down the make and model of my calculator
Was so stressed. Just opened the paper. Does anyone know if it is a problem?

I'm 99.9999% sure it isn't at all.

Paddi Jones

Crap reading all this is totally killing my confidence, its seriously looking like I didn't pass, I really gotta stop dwelling on this crap, its just such a freakin' downer.

teacher30

Guys - i really admire u doing honours maths, i did Pass 12 yrs ago! Pat yourselves on the back for doing it

Secondly - rememebr that most people found it tough. And VERY OFTEN the people who think they didn't do well are the ones who get better results than the ones who think they flew it!! I'm serious - i see it every yr on results day

And when u feel that you've done well, be modest about it - think of ur pals who found it hard.

Keep the chin up everyone,
James

teacher30

Don't be so hard on yourself.
Remember you get marks for every effort u make.
Don't be on a downer - other exams will go well for you, i promise!

have a rest for yourself this evening
james

EuropeanSon

teacher30 wrote: »

Guys - i really admire u doing honours maths, i did Pass 12 yrs ago! Pat yourselves on the back for doing it

Secondly - rememebr that most people found it tough. And VERY OFTEN the people who think they didn't do well are the ones who get better results than the ones who think they flew it!! I'm serious - i see it every yr on results day

And when u feel that you've done well, be modest about it - think of ur pals who found it hard.

Keep the chin up everyone,
James

What is this word "modest"?

Seriously though, it's true. Only 8 in my school did honours maths, me included. Most found it too tough. Even a pass is a pretty good achievement, it puts you above 80% of the country, at a minimum.

SantryRed

Exactly.

NumberZeroNine

zam wrote: »

Well I said 16p^2 > -1
But I'm sure your answer merits the bulk of the marks!

His answer is what you should be setting out to prove, that a sum of perfect squares and known, positive constants is greater then zero.

zam

NumberZeroNine wrote: »

His answer is what you should be setting out to prove, that a sum of perfect squares and known, positive constants is greater then zero.

True. At the same time though, a real number squared times 16 is obviously greater than -1.

almostnever

Paddi Jones wrote: »

Crap reading all this is totally killing my confidence, its seriously looking like I didn't pass, I really gotta stop dwelling on this crap, its just such a freakin' downer.

I promise you, boards does not represent a typical cross section of Irish Leaving Certs. I remember last year having a complete panic attack when what I deemed to be a horrendous physics paper was being described by many to be "piss easy." I'm sure you're done better than you think, I was 100% convinced I'd failed it last year but I got a D2.

I know it's hard, but try to focus on the exams you still have to do. You'll be fine.

SantryRed

We're all smart on Boards

I joke...

teacher30

I know how you feel. I think there's a slight arrogance in some people saying: OMG it was so easy!! Ignore them! They'll face challenges in other exams that you'll probably fly through!!

mercurypink

The algebra was delicious. The complex numbers, however... not so delectable.

MollyJayne

Ok. In reply to everything...

It was a very nice paper, and I think paper two will be the same!

1. c) iii) so annoyed! I got b=-4 and d=6, but somehow I made c=-3-b = c=-3-4=7, when it should have been c=-3+4=1...only realised now! Kept trying to figure out what I'd done wrong... I'd decided to change d to -10 so it would fit the sequence, but it didn't fit the equation =[
The right answers are definitely -4, 1, 6 as they fit the sequence and the equation...

Another controversial issue...
6. b) ii) It's definitely a curve. It says in the question that its a curve. Yup, parametric equations of a CURVE.
I don't know the answer though... I was going to say that its increasing but if its a curve...it curves!

I thought question 8 was lovely! Didn't quite get the last part of c out 'cause I ran out of time (shouldn't have kept checking that question 1!) but should get most of the marks for it...

I think I got atleast 65% in that paper, and I always find paper two easier so I'm really hoping for a B at this stage!