* Honours Maths paper 1 * AFTERMATH

Kedo93

Hey guys, without doubt that paper today was quite a bitch. I understand most of it now but I really can't get my head around the B part (ii) on question 6.
You had to find the turning point on y=e^-x^2. Well i differentiated and got dy/dx = -2x.e^-x^2. To get turning points you set dy/dx=0 but this gives -x^2 =Ln0 which is undefined. I'm really stumped because I previously thought exponential functions weren't even meant to have a turning point?
Can anybody explain to me how you went around doing this question?
Thanks and good look on paper 2 everyone!

Paczini

JamieDOC wrote: »

I got 2XSquared..I hope I didn't get yet another question completely wrong.

I've got 2x^2 as well

electrictrad

. . .without starting a riot, can anyone answer q2 part c iii. . .I got a > 10-(x+3)^2 and a >=9, but I think Im probably wrong. . . .

PJelly

This is how I got the disc question out... not sure if it's right though...
Circle integral is Y^2=R^2 - X^2
So disc is Y= root R^2 and X^2
Then it's one of those "Let X = rsintheta. things". Your limits turn out to be pi over two and pi over two.
Then you end up integrating R^2 over two - R^2 over two cos 2 theta.
Sub in your values, and remember pi!
Shiz cancels, and you get R^2pi over two.
This is a semi circle (I assumed) so multiply by two.
PiR^2. I made sure to put in a reason as to why I was multiplying by two.
I THINK that's the way to do it..

Also, how did you all do B (ii) in integration. I was sure I did it right, but I'm hearing conflicting reports from friends...

lauratkd

Just did the solutions fully and realised there isn't a mistake in 7bi. It's just mean!

Dbstf

http://examinations.ie/archive/exampapers/2011/LC003ALP100EV.pdf

OMG Im so glad i moved down to pass maths this looks freaking impossible :S

AnneElizabeth

Got as far as the part, had a mini heart-attack then ditched the rest of the question :P

C14N

PJelly wrote: »

This is how I got the disc question out... not sure if it's right though...
Circle integral is Y^2=R^2 - X^2
So disc is Y= root R^2 and X^2
Then it's one of those "Let X = rsintheta. things". Your limits turn out to be pi over two and pi over two.
Then you end up integrating R^2 over two - R^2 over two cos 2 theta.
Sub in your values, and remember pi!
Shiz cancels, and you get R^2pi over two.
This is a semi circle (I assumed) so multiply by two.
PiR^2. I made sure to put in a reason as to why I was multiplying by two.
I THINK that's the way to do it..

Also, how did you all do B (ii) in integration. I was sure I did it right, but I'm hearing conflicting reports from friends...

B(ii) was okay. You just had to make it go from

x^2 + 2x + 2

to

x^2 + 2x + 1 + 1

Then make it

(x+1)^2 + 1


Looking back, I think I made a mistake though in cancelling the top line with the bottom.:(

LilMissCiara

lauratkd wrote: »

Just did the solutions fully and realised there isn't a mistake in 7bi. It's just mean!

Echo, echo, echo..! :P

oldyouth

I have an inconsolable son who did everything that could have been asked of him over the last 5 years in 2nd level education. He feels as if his future plans are in doubt because of this paper.

I know very little about the exam or it's contents, whether it was fair or unfair but I tell you this, if the gobsheeen setting the paper was on some sort of ego trip to leave his/her mark on the leaving cert at the expense of these young people, then Karma is heading his/her way. Maybe not today or tomorrow, but it is coming.

Patriciamc93

Kedo93 wrote: »

Hey guys, without doubt that paper today was quite a bitch. I understand most of it now but I really can't get my head around the B part (ii) on question 6.
You had to find the turning point on y=e^-x^2. Well i differentiated and got dy/dx = -2x.e^-x^2. To get turning points you set dy/dx=0 but this gives -x^2 =Ln0 which is undefined. I'm really stumped because I previously thought exponential functions weren't even meant to have a turning point?
Can anybody explain to me how you went around doing this question?
Thanks and good look on paper 2 everyone!

When i let it equal to 0 i got
-2x=0 and e^-x^2 =0 as the roots and then I only took the -2x=0 and got x=0 as the x-coordinate.

PJelly

C14N wrote: »

B(ii) was okay. You just had to make it go from

x^2 + 2x + 2

to

x^2 + 2x + 1 + 1

Then make it

(x+1)^2 + 1


Looking back, I think I made a mistake though in cancelling the top line with the bottom.:(

Annd.. why did you have to do that? D=
I let U equal the top. And the bottom was half Du. so I got U over one.
Which was just U
Then I had U^2 over two. Ended up with 24 at the end.

aranciata

Were the answers for 8(b)(i) and (ii), ln(3) and ln(3) + 6?

RoryInLeitrim

for 7(b)(ii) i wrote: C is the correct answer,i hope....

margebaxter

C14N wrote: »

Why are the limits 0 and pi? If there was a radius of r, why weren't they r and (-r)?

Don't ask my why but you had to change the limits to 0 and pi/2 by means of rcostheta=x blah blah blah.

I'm royally pissed off. Banking on an A. Totted up my marks (as you do when you lose all hope in an exam). I've skimmed a B3 at the very highest. Gutted.

partyatmygaff

oldyouth wrote: »

I have an inconsolable son who did everything that could have been asked of him over the last 5 years in 2nd level education. He feels as if his future plans are in doubt because of this paper.

I know very little about the exam or it's contents, whether it was fair or unfair but I tell you this, if the gobsheeen setting the paper was on some sort of ego trip to leave his/her mark on the leaving cert at the expense of these young people, then Karma is heading his/her way. Maybe not today or tomorrow, but it is coming.

I put my life and soul in to Maths the past two years. I wanted to get an A and I doubt I can now. I literally worked on my maths every single day for the past year and it's all gone to waste now because of this rubbish paper.

We all feel your son's pain.

River Song

margebaxter wrote: »

Don't ask my why but you had to change the limits to 0 and pi/2 by means of rcostheta=x blah blah blah.

I'm royally pissed off. Banking on an A. Totted up my marks (as you do when you lose all hope in an exam). I've skimmed a B3 at the very highest. Gutted.

Exact same.

electrictrad

aranciata wrote: »

Were the answers for 8(b)(i) and (ii), ln(3) and ln(3) + 6?

I got ln(root5) and 4 + ln3. . . .same territory, so one of us has just blundered, i'd say

River Song

margebaxter wrote: »

Don't ask my why but you had to change the limits to 0 and pi/2 by means of rcostheta=x blah blah blah.

I'm royally pissed off. Banking on an A. Totted up my marks (as you do when you lose all hope in an exam). I've skimmed a B3 at the very highest. Gutted.

Exact same.

Listening to the thunder, my granddad immediately said "Oh, God must be p****d off about the maths too!"

Gileadi

To me it didn't seem overly difficult, all the questions were from the curriculum. I do feel that students can get too familiar with certain past questions, learning how to answer the individual question rather than fully understanding the underlying concept.

This over familiarity with past papers leads to students feeling that any deviation from a previously seen question is outlandishly hard (as some may feel tonight).

Best of luck anyway in paper II gach duine!

partyatmygaff

I wouldn't worry all too much about the disc integration question. Considering most people had never even heard of the proof, i'd say that the marking scheme will be changed to award the majority of the marks for drawing the diagram and completing the circular integral.

randylonghorn

oldyouth wrote: »

I have an inconsolable son who did everything that could have been asked of him over the last 5 years in 2nd level education. He feels as if his future plans are in doubt because of this paper.

I know very little about the exam or it's contents, whether it was fair or unfair but I tell you this, if the gobsheeen setting the paper was on some sort of ego trip to leave his/her mark on the leaving cert at the expense of these young people, then Karma is heading his/her way. Maybe not today or tomorrow, but it is coming.

oldyouth, can I just draw your attention to my post here?

I know it's tough when a paper goes horribly, but it seems to be the same for everyone, which is actually good news for everyone!

Best thing you can do for your son is to encourage him to go out in a field (if available!), scream, curse, kick something if necessary, get it out of his system, and then let it go, and to concentrate on what is ahead.

niamhallen

electrictrad wrote: »

. . .without starting a riot, can anyone answer q2 part c iii. . .I got a > 10-(x+3)^2 and a >=9, but I think Im probably wrong. . . .

that's what I said, hopefully it's right..

Shayanzadeh

C14N wrote: »

Why are the limits 0 and pi? If there was a radius of r, why weren't they r and (-r)?

Like I said, I had never seen that question, that was me tackling the question for the first time, and it worked out! I see where you are coming from, I did it with -r and r and it didn't work. I took the 0 and Pi, from the unit circle, the angle at the edges of the circle. I thought since we need Pi in the answer and we had sin theta...I hope I get the marks

drg85

red_red_wine wrote: »

Well it says 'based on the derivatives' and it tells you that f'(x) = g'(x)...surely that's enough of a justification for saying that the slopes are always the same and also that it is decreasing (given that the derivative is always < 0).

Only that, on a technicality, that solution is in part undefined. The question clearly states the function exists between [0,-1] when infact you must assume it extends into the positive axis. Had I been sitting the paper, that alone would have thrown me. Couple that with a few other technical errors (the whole arctan of an undefined value is utterly stupid, and really glaring) I didn't think it was at all a fair question. I already have my LC, my BSc and my PhD at this stage but had I been sitting the exam I wouldn't have liked it, and Im the kind of nerd who usually likes exams. Just sayin' I felt that was harder than 8(c) as it actively punished students who knew 'too much' or knew something about undefined functions

margebaxter

Gileadi wrote: »

To me it didn't seem overly difficult, all the questions were from the curriculum. I do feel that students can get too familiar with certain past questions, learning how to answer the individual question rather than fully understanding the underlying concept.

This over familiarity with past papers leads to students feeling that any deviation from a previously seen question is outlandishly hard (as some may feel tonight).

Best of luck anyway in paper II gach duine!

Well the man himself, Brendan Guildea, was on RTE earlier. Said the paper was shambolic. If the god of maths says so. Listen, an abstract thinker may have devoured that paper. But the course is so time consuming that it simply allows nothing in terms of time to become an 'abstract thinker'. You learn what you know will come up and you prepare for the worst case scenario.... Who knew how far they could expand on the concept of 'worst case scenario'. :P

jumpguy

oldyouth wrote: »

I have an inconsolable son who did everything that could have been asked of him over the last 5 years in 2nd level education. He feels as if his future plans are in doubt because of this paper.

I know very little about the exam or it's contents, whether it was fair or unfair but I tell you this, if the gobsheeen setting the paper was on some sort of ego trip to leave his/her mark on the leaving cert at the expense of these young people, then Karma is heading his/her way. Maybe not today or tomorrow, but it is coming.

Ah now, poor lad. I'd say if he did his best and attempted every question he'd be grand. The marking scheme will be very fair this year. Tell him not to dwell on paper 1 now, and recouperate for paper 2 on Monday.

Jaafa

I did the paper too. Though it was bad I think everyone needs to take it easy for a while. Here ya go:

http://www.youtube.com/watch?v=LanCLS_hIo4

firestarter197

Here are some bits. If anyone seems any problem with those, let me know. People are saying different things about what they got...

http://i253.photobucket.com/albums/hh48/devilboy197/bits.jpg

Patri

partyatmygaff wrote: »

I put my life and soul in to Maths the past two years. I wanted to get an A and I doubt I can now. I literally worked on my maths every single day for the past year and it's all gone to waste now because of this rubbish paper.

We all feel your son's pain.

I'm the very same. Maths was the only exam I felt fully prepared for. I got an A in the mocks, I've done 3 more mocks since then in which I got two B1s and an A1 and I was banking on this for an A. I think my dreams of medicine have been compromised, I literally felt like I failed. So disappointing after English aswell...