OL Maths paper 2

ldxo15wus6fpgm

drurz57 wrote: »

can someone tell me, why does the 38.4 have to be rounded up to 39 and not 38?

Aoifey! wrote: »

I was wondering that too? I rounded down :S

It's because it was something like 38.467 and that means you round starting from the 7. the 7 makes the 6 a 7, and that 7 makes the 4 a 5. so you would have 38.5 which rounds to 39.

Cipango

garv123 wrote: »

i found it really easy. anyone know what the radius was for 1 part c

I got something like 2.4 (thereabouts)

RyanK

Cipango wrote: »

I got something like 2.4 (thereabouts)

3.4 - I think I did that question in my own little (slightly confusing) way but got the same answer as others posting on this board. How did you guys solve it?

Finical

Damn it I got radius 1. something.

Oh well was happy with the rest of my questions but probability was tricky for me.

loocas

Channing Sticky Coffin wrote: »

It's because it was something like 38.467 and that means you round starting from the 7. the 7 makes the 6 a 7, and that 7 makes the 4 a 5. so you would have 38.5 which rounds to 39.

Except in pass maths!

I pulled this stunt in the mocks and lost 3 marks for incorrect answer for some bollox reason. Teacher backed up the examiner and said they were right, "it should go down to (example above) 38". Mind you she's not all that right in the head. Came down from Honors maths for 6th year pulling all kinds of crazy stunts, they were having none of it!

bobsy

I got somethink like 1.4 for 1c(i).Thought it was a fairly easy paper if you were prepared.

Cipango

RyanK wrote: »

3.4 - I think I did that question in my own little (slightly confusing) way but got the same answer as others posting on this board. How did you guys solve it?

It gave you the volume of the sphere so I added the vol of cone plus the vol of cylinder and equaled it to the vol of sphere and subbed it what I had and got my radius....simples!

I'm wrong aren't I!

Captain-America

Cipango wrote: »

It gave you the volume of the sphere so I added the vol of cone plus the vol of cylinder and equaled it to the vol of sphere and subbed it what I had and got my radius....simples!

I'm wrong aren't I!

That's what I did! Got 7.5.

UpTheSlashers

Is the volume of a cone one third the volume of a cylinder if the radius and height are the same?

Cipango

Captain-America wrote: »

That's what I did! Got 7.5.

I may have made a mistake with cancelling out the pies or something but still that's only -3m and still get 94% in that question.

RyanK

UpTheSlashers wrote: »

Is the volume of a cone one third the volume of a cylinder if the radius and height are the same?

Yea that's what I did. From that you could get the volume of the cylinder and cone alone. And therefore work out the radius.

Eire-Dearg

I did the Vol of Cylinder + Vol of Cone = Vol of Sphere and ended up with 3.4 or something in the 3s.

7 is far too big think, the height was 8!

Duncannon

Cook!eMonster wrote: »

anybody else think it was simply AWFUL?

The general view is that it was easier than paper 1

Duncannon

Cipango wrote: »

Im pretty sure i got an A1 in todays paper, however as good as that sounds that shaggin Paper 1 ruined my grade!! RUINED!! Was fairly confident i was going to get an A2 overall......i can kiss that goodbye!!!

I reckon that paper ! will be marked easy because of the difficult bits in Q3c and 7c

Duncannon

SirDarren wrote: »

Exact same. I can't see the difficulty really

You are right there was no problem with the vectors

Duncannon

Channing Sticky Coffin wrote: »

It's because it was something like 38.467 and that means you round starting from the 7. the 7 makes the 6 a 7, and that 7 makes the 4 a 5. so you would have 38.5 which rounds to 39.

ou can round it either way

ldxo15wus6fpgm

Duncannon wrote: »

ou can round it either way

Nope :P from .5 upwards, you round up. You only round down if it's .4 or less. If we could all pick which way we'd like to round, it would be pretty confusing.

Cipango

Duncannon wrote: »

I reckon that paper ! will be marked easy because of the difficult bits in Q3c and 7c

Hopefully! Need a high grade to get into my course.

RetroRainbow

Surprisingly, I didn't find it as hard as I thought I would. The extra few hours spent late last night doing questions from past exam papers paid off! I kept telling myself, 'all you need is 40% to pass, all you need is 40%...', and that set my motivation skyrocketing. Felt like I did much better than last year anyway, which is good.

Duncannon

Channing Sticky Coffin wrote: »

Nope :P from .5 upwards, you round up. You only round down if it's .4 or less. If we could all pick which way we'd like to round, it would be pretty confusing.

38.467 they wil accept 38 for that because it is less than 38.5 even if you round up to 38.5 convention says that this is can be 39 or 38 see wiki

Duncannon

Channing Sticky Coffin wrote: »

Nope :P from .5 upwards, you round up. You only round down if it's .4 or less. If we could all pick which way we'd like to round, it would be pretty confusing.

there is no convention on this written in stone

MathsManiac

Since the true answer (with full accuracy) is closer to 38 m than to 39 m, it follows that 38 m is the only correct answer to the question "Find ... to the nearest metre".

(What they might accept, of course, is another matter!)

ldxo15wus6fpgm

Duncannon wrote: »

there is no convention on this written in stone

Fair enough, I have always been taught to start at the smallest digit and work your way across

MathsManiac wrote: »

Since the true answer (with full accuracy) is closer to 38 m than to 39 m, it follows that 38 m is the only correct answer to the question "Find ... to the nearest metre".

(What they might accept, of course, is another matter!)

Taken from wiki:

Rounding a number twice in succession to different precisions, with the latter precision being coarser, is not guaranteed to give the same result as rounding once to the final precision except in the case of directed rounding. For instance rounding 9.46 to one decimal gives 9.5, and then 10 when rounding to integer using rounding half to even, but would give 9 when rounded to integer directly.

I'll accept that 38 is acceptable but there's no way you can say it's the only right answer.

ihavequestions

I did the last part of the trig question again yesterday, my answer was 38.401 which became 38. i did it 3 times, including all decimals,which is how i always do it.dont see how someone could have gotten 39 tbh,but imo they will accept both answers,providing all the relevant work is shown

Duncannon

Channing Sticky Coffin wrote: »

Fair enough, I have always been taught to start at the smallest digit and work your way across



Taken from wiki:

Rounding a number twice in succession to different precisions, with the latter precision being coarser, is not guaranteed to give the same result as rounding once to the final precision except in the case of directed rounding. For instance rounding 9.46 to one decimal gives 9.5, and then 10 when rounding to integer using rounding half to even, but would give 9 when rounded to integer directly.

I'll accept that 38 is acceptable but there's no way you can say it's the only right answer.

There is a lot of talk about yesterdays project maths papers the higher seems to be really dumbed down .They asked the same Theorem question on the Higher and the ordinary .
any views

Duncannon

Cipango wrote: »

Im pretty sure i got an A1 in todays paper, however as good as that sounds that shaggin Paper 1 ruined my grade!! RUINED!! Was fairly confident i was going to get an A2 overall......i can kiss that goodbye!!!

dont worry about paper 1 its over

Duncannon

Lawliet wrote: »

Yeah I couldn't get that to work out at all, keep going up with ridiculous answers, I'm just hoping they'll give me a few attempt marks.

The image of B was C(-13,19) so the length |AC| = 25 then the ratio of |AB|:|AC|= 10:25=2:5

xDancingQueenx

I thought it was great I flew through it !!!

Duncannon

xDancingQueenx wrote: »

I thought it was great I flew through it !!!

good news

MathsManiac

Channing Sticky Coffin wrote: »

Taken from wiki:

Rounding a number twice in succession to different precisions, with the latter precision being coarser, is not guaranteed to give the same result as rounding once to the final precision except in the case of directed rounding. For instance rounding 9.46 to one decimal gives 9.5, and then 10 when rounding to integer using rounding half to even, but would give 9 when rounded to integer directly.

I'll accept that 38 is acceptable but there's no way you can say it's the only right answer.

Of course you can. The Wikipedia article is simply pointing out that rounding more than once can result in getting the mathematically incorrect answer. Unless the fractional part of a number is 0.5, then only one integer can be the closest integer to it.

The true (unrounded) answer to the question is sqrt(1049.76 + 302.76*(tan 50)^2 ) metres. The closest integer to this is 38 m. Since 39 m is farther away, it is not the correct answer, although they may choose not to penalise it.