!! Maths HL paper 1 2016 - Before and After

onlinenerd

Such a nice paper

RC12397

Anybody else get 40π for The rate that the radius is increasing?

DownOneTourist

do ye get something like -1+2i for 1c?
Also was the inverse function just 1 over (3x-2)?
Also for the differenciation question does 128pi/3 ring any bells?
I got 52 degrees in the acute question,
3.2 and 1.6
was question one a just the the complex conjugate?
anyone else get 0.15 for the slope of the curve?
also that javelin question was beautiful!

Edrees98

It was a lovely maths paper but I made a few silly mistakes to be honest. Hopefully I got a low A2 or a B1.

Lee_la

Thought it was a lovely paper but after reading everyone else's answers here, I don't think it went as well as I originally thought..

DownOneTourist

Edrees98 wrote: »

It was a lovely maths paper but I made a few will mistakes to be honest. Hopefully I got a low A2 or a B1.

I feel the same. I definitely think that i got above 80 but i'm not sure by how much.

https://www.examinations.ie/tmp/1465577640_6345312.pdf Leela tell us what you got if you can remember!

Edrees98

People are saying (3.2,1.6) for question 8(b) but it says distance. How could you get a coordinate???

DublinArnie

Edrees98 wrote: »

People are saying (3.2,1.6) for question 8(b) but it says distance. How could you get a coordinate???

No, part c wants the coordinates.

I got 8m for the distance. Idk if it's right.

pseudorachel

Edrees98 wrote: »

People are saying (3.2,1.6) for question 8(b) but it says distance. How could you get a coordinate???

that's for part c.
part b is the limited at infinty of the sum of the series which was 8.

legocrazy505

Just after roughly allocating marks and probably got a B3 or somewhere around that. Will need to make sure paper two secures a B at least since a B3 is required for my first choice.

onlinenerd

pseudorachel wrote: »

that's for part c.
part b is the limited at infinty of the sum of the series which was 8.

You are referring to question 9 I think

DownOneTourist

8 is the distance 4 over 1-1/2 i think is what i had

Edrees98

pseudorachel wrote: »

that's for part c.
part b is the limited at infinty of the sum of the series which was 8.

I got 8, soo am I right??

louisoc

DownOneTourist wrote: »

do ye get something like -1+2i for 1c?
Also was the inverse function just 1 over (3x-2)?
Also for the differenciation question does 128pi/3 ring any bells?
I got 52 degrees in the acute question,
3.2 and 1.6
was question one a just the the complex conjugate?
anyone else get 0.15 for the slope of the curve?
also that javelin question was beautiful!

I'm pretty sure it was 1-2i for that complex num q

MashedPotato49

Yep

DownOneTourist

louisoc wrote: »

I'm pretty sure it was 1-2i for that complex num q

you might be right. I remember the numbers and that was a minus sign somewhere. I divided a Z factor into the Z squared equation and got a root from the factor at the top

louisoc

DownOneTourist wrote: »

you might be right. I remember the numbers and that was a minus sign somewhere. I divided a Z factor into the Z squared equation and got a root from the factor at the top

I just did it there and 1-2i fits z^2 - sum + product. My chemistry teacher was going through the exam afterwards and he said there were about five different ways of doing that q

Lee_la

For Q1 (b) and (c) I got something + 0i
For the inverse function I got (x+2) over 3
For the rate the radius increases I got 5/32pi
For the rate the surface area increases I got 40000pi
For the average height of the ball I think I got 166.667
For the acute angle I got 1 degree which I obviously went wrong with :')

Heyzelx

Pure babe of a paper!!!!

DownOneTourist

louisoc wrote: »

I'm pretty sure it was 1-2i for that complex num q

Lee_la wrote: »

For Q1 (b) and (c) I got something + 0i
For the inverse function I got (x+2) over 3
For the rate the radius increases I got 5/32pi
For the rate the surface area increases I got 40000pi
For the average height of the ball I think I got 166.667
For the acute angle I got 1 degree which I obviously went wrong with :')

well i got your average height! And i think i did the inverse function wrong. Can anyone explain how to do that inverse. and i totally did the radius rate and suface area questions wrong

emersyn

How are you all able to remember exactly what you got?? I haven't a notion of what any of my answers were

Edrees98

DownOneTourist wrote: »

well i got your average height! And i think i did the inverse function wrong. Can anyone explain how to do that inverse. and i totally did the radius rate and suface area questions wrong

For the inverse, you let the function equal y, then you try and get the x independent. When that is done replace the y with an x and there ya go.

DublinArnie

DownOneTourist wrote: »

well i got your average height! And i think i did the inverse function wrong. Can anyone explain how to do that inverse. and i totally did the radius rate and suface area questions wrong

That average height is impossible because if you graph the function it's max is like 24 I think.

You guys made the same mistake like I did by forgetting to multiply your final answer by 1/b-a. I saw it and corrected it in the end.

Average height is 16.66 I think? Makes more sense.

Appmaths97

how were you supposed to show that 3x-2 was injective ?

luftmensch

Does anyone know whether or not you will be penalised for not including units in your answers?

themadscone

Anyone know when provisional marking schemes go up? Currently bricking it as i forgot to work out the point the line is approching in q8... Just filled in the table and moved on:( hoping its not worth too much...

luftmensch

Appmaths97 wrote: »

how were you supposed to show that 3x-2 was injective ?

I plotted it, and then used the horizontal line test.

skippy1977

themadscone wrote: »

Anyone know when provisional marking schemes go up? Currently bricking it as i forgot to work out the point the line is approching in q8... Just filled in the table and moved on:( hoping its not worth too much...

Marking scheme won't go up until the day the Leaving Cert results come out...

luftmensch

themadscone wrote: »

Anyone know when provisional marking schemes go up? Currently bricking it as i forgot to work out the point the line is approching in q8... Just filled in the table and moved on:( hoping its not worth too much...

After the results I think

skippy1977

DublinArnie wrote: »

That average height is impossible because if you graph the function it's max is like 24 I think.

You guys made the same mistake like I did by forgetting to multiply your final answer by 1/b-a. I saw it and corrected it in the end.

Average height is 16.66 I think? Makes more sense.

Yep that's the answer.

Appmaths97

luftmensch wrote: »

I plotted it, and then used the horizontal line test.

It was such a stupid question because it the function is linear it is always injective.

emersyn

luftmensch wrote: »

I plotted it, and then used the horizontal line test.

I did this too and I just realised that I didn't label which question the graph was for on the graph paper - does anyone know if this will matter? That graph was the only thing I wrote on the page and it was the only extra page I handed up and in the space given on the exam paper itself I wrote 'SEE GRAPH PAPER'

pseudorachel

luftmensch wrote: »

Does anyone know whether or not you will be penalised for not including units in your answers?

you'll be docked a mark if you leave out the units but there wasn't that many on the paper anyway

skippy1977

emersyn wrote: »

I did this too and I just realised that I didn't label which question the graph was for on the graph paper - does anyone know if this will matter? That graph was the only thing I wrote on the page and it was the only extra page I handed up and in the space given on the exam paper itself I wrote 'SEE GRAPH PAPER'

I'd say you'll be grand, the examiner should cop this. Especially if you wrote it on the exam.

Edrees98

DublinArnie wrote: »

That average height is impossible because if you graph the function it's max is like 24 I think.

You guys made the same mistake like I did by forgetting to multiply your final answer by 1/b-a. I saw it and corrected it in the end.

Average height is 16.66 I think? Makes more sense.

So did I ...... Most we can lose is 2 I hope.

luftmensch

emersyn wrote: »

I did this too and I just realised that I didn't label which question the graph was for on the graph paper - does anyone know if this will matter? That graph was the only thing I wrote on the page and it was the only extra page I handed up and in the space given on the exam paper itself I wrote 'SEE GRAPH PAPER'

Fuuuuuuuuuuuuu...

I just realised that I never wrote the question number for any of the work I did on the extra spaces at the back.



Will i be penalised for this. One of the questions I did at the back was the differentiation from first principles. I got it wrong the first time so I re-did at the back. No labels though

Would the examiner be cool about it? I mean it's obvious what question it is right?

DublinArnie

You can also prove it's injective by subbing in different outputs and proving they only have one input.

Edrees98

DublinArnie wrote: »

You can also prove it's injective by subbing in different outputs and proving they only have one input.

I did that and the graph yolk. Weird question though.

luftmensch wrote: »

Fuuuuuuuuuuuuu

I just realised that I never wrote the question number for any of the work I did on the extra spaces at the back.

You shouldn't really lose marks.

BrownTrout

Handy enough paper, think I got everything bar the angle of the basketball.

Probably means it will be marked very harshly, everyone seems to be happy with it...

legocrazy505

BrownTrout wrote: »

Handy enough paper, think I got everything bar the angle of the basketball.

Probably means it will be marked very harshly, everyone seems to be happy with it...

I know that's my worry about it. Got to keep the bell curve alive.

Appmaths97

what's the derivative of sin (1 divided by x)
is it -1 over x squared by cos(1 divided by x)

DublinArnie

Appmaths97 wrote: »

what's the derivative of sin (1 divided by x)
is it -1 over x squared by cos(1 divided by x)

I did the product rule since it was x multipled by the trig.

From memory, I think I got -x^-1cos1/x + xsin1/2

I think I messed that question up to be honest.

skippy1977

Very nice paper. Unreal straight forward opening 6 questions, no tricks or difficult wording.
Q7 was lovely, you couldn't get a more straight forward rate of change question. (b) (i) was Junior Cert level and the only thing in part (ii) was whether people would spot that 'average height' means integrate the function from 0 to 10 and divide times by 1/b-a.
Q8 was a bit tricky but okay...not dissimilar to questions people would have done before (last years plane landing, the bridge question on another sample). (b) part was just substitution...working with logs at the end.
Q9 looked harder than it was...once you established what numbers where in the geometric sequence you just had to apply...Sn and sum to infinity formulae.

Overall I think people will be happy...don't worry about people saying that things will be marked harder....if you got questions right or mostly right they will still be right!

No learned stuff...so expect a bit in Paper 2.

malnurtured

DublinArnie wrote: »

I did the product rule since it was x multipled by the trig.

From memory, I think I got -x^2cos1/x + xsin1/2

I think I messed that question up to be honest.

Wouldn't it be (-x^-2)cos(1/x) + xsin(1/x)?

The derivative of 1/x (x to the negative one) is -x^-2 right? Multiply that in to the cos(1/x)?

I got my answer for that as -0.77. Anyone else?

DublinArnie

malnurtured wrote: »

Wouldn't it be (-x^-2)cos(1/x) + xsin(1/x)?

The derivative of 1/x (x to the negative one) is -x^-2 right? Multiply that in to the cos(1/x)?

I got my answer for that as -0.77. Anyone else?

Yeah, but when you multiply x^-2 with x you get x^-1 because you add/minus the powers.

Is that correct? I'm losing it .

Ah ****e, I meant to write -x^-1cos1/2 + xsin1/x in the post above.

luftmensch

luftmensch wrote: »

Fuuuuuuuuuuuuu...

I just realised that I never wrote the question number for any of the work I did on the extra spaces at the back.



Will i be penalised for this. One of the questions I did at the back was the differentiation from first principles. I got it wrong the first time so I re-did at the back. No labels though

Would the examiner be cool about it? I mean it's obvious what question it is right?

Actually, does anyone know if I could/should write a note on Mondays paper 2 indicating the unlabelled questions I did on the back of paper 1?

malnurtured

DublinArnie wrote: »

Yeah, but when you multiply x^-2 with x you get x^-1 because you add/minus the powers.

Is that correct? I'm losing it .

Yeah that's right, I can't remember if I did that or not, lol. Did you get -0.77 for the bit where you had to sub in afterwards?

DublinArnie

malnurtured wrote: »

Yeah that's right, I can't remember if I did that or not, lol. Did you get -0.77 for the bit where you had to sub in afterwards?

I remember getting a double decimal like that, 95% confidence interval that I'm sure.

Seaaan

Reading everyone's confidence just makes me feel worse For the basketball angle one I just did tan inverse of opposite over adjacent and got 50 something, what's this about slopes??

malnurtured

DublinArnie wrote: »

I remember getting a double decimal like that, 95% confidence interval that I'm sure.

Ah I'll get most of the marks, be grand. Was hoping for a B3 going in, definitely got that at least. Roll on P2

Seaaan wrote: »

Reading everyone's confidence just makes me feel worse For the basketball angle one I just did tan inverse of opposite over adjacent and got 50 something, what's this about slopes??

I did opposite over adjacent too, was that not right? Seemed to be. I got like 34 degrees though I may have mixed up the x and y co-ords, hilariously enough