Junior Cert 2011 : Maths Paper 2

Colm!

scipsss wrote: »

Eh you all might think this is strange but i don't know what pythagorous's theorem is ? i thought it was like h squared + r squared = l squared or something like that ?

Quick description in MS Paint:


That's not how you prove the theory, but it should show you how to apply it in exam questions. I'll try and find the proof as it's a bit long and I can't really draw it up in Paint.

omg a kitty

scipsss wrote: »

Eh you all might think this is strange but i don't know what pythagorous's theorem is ? i thought it was like h squared + r squared = l squared or something like that ?

Quick summary of what Colm explained:
If you have a right angled triangle, and they tell you the two sides that make up the right angle, you can find out what the hypotenuse is(the side opposite to the right angle).
Say if it was 3 and 4, so
3^ + 4^ = hypotenuse^
9 + 16 = hypotenuse^
25 = hypotenuse^
sq.root of 25 = hypotenuse
5 = hypotenuse

^ means squared

They could come up in Paper 2 Q5, but the question might not be that direct, and I think it could come up in Q3 aswell

Slow Show

Oh wow I'd love if Pythagoras somehow came up in a part C, so wonderfully easy . They tend to save it for trigonometry though, sigh. Ummm the standard proof for good ole Pythag is....

OK, I just did a quick search online and the proof of the theorem is quite elusive, I know I found all the theorems and their proofs online one day, if I stumble across it I'll stick it up here. But anyway, I don't actually use the standard proof for Pythagoras, I found it really hard to remember, I use a method using a square...it's kinda hard to explain, but it's wonderfully easy and if anyone wants me to I'll try explain it. You're really unlikely to be asked on it though, sadly.

ScummyMan

Gah, project maths

Ye are all so lucky to be doing a normal Paper 2, Project Maths is so impossibly hard

We dont even know how many questions there will be, all we have to go on is 1 sample paper :eek:

KaBooom

Im getting worried about paper 2, cant wrap my head around these theorems at all, didnt pay much attention to them in class and I dont know any of them off by heart.. Instead of learning them today, I calculated the highest grade i can get if I skip all the theorems questions :L

King John The Last

Explain it! I want to remember Pythrogas and I cant remember my teachers way.

buyer95

Does anyone know like the key theroems to know? Like what are likely to be asked... I dont know all of them that well and I'm kind of panicking now, no time to learn them all... Any tips?

Slow Show

It's hard to explain, I'll write it out and try scan it up or something in a bit, it can count as studying. :pac:

Desire.

buyer95 wrote: »

Does anyone know like the key theroems to know? Like what are likely to be asked... I dont know all of them that well and I'm kind of panicking now, no time to learn them all... Any tips?

If you had to learn one theorem, learn the circle theorem, number seven.

JC2011girl

Can anyone give me a brief description of the different questions for example
Q6- statistics? Thanks

Desire.

JC2011girl wrote: »

Can anyone give me a brief description of the different questions for example
Q6- statistics? Thanks

If you're looking for the different type of questions that are asked just look at your exam papers?

JC2011girl

Oh and a quick question about P1, for Q6b ii) I got 4.5 and 2.5 when the answr was -4.5 and 2.5.. How many marks do you think I'll lose for getting the wrong sign?

Slow Show

Alternative (and imo, easier) version of Pythagoras:


Procrastination has reached new levels...:o and if you can't read my writing, sorry, that took a huge effort to make it as neat as it is, it's usually almost incomprehensible

EDIT: Oh jesus, that's massive...

King John The Last

Thats a hell of a lot shorter than our version, thanks.

Desire.

JC2011girl wrote: »

Oh and a quick question about P1, for Q6b ii) I got 4.5 and 2.5 when the answr was -4.5 and 2.5.. How many marks do you think I'll lose for getting the wrong sign?

A blunder, three marks.

Colm!

In case you can't read Slow Show's handwriting, I did up this. I've never seen the Alternate Proof before, but it's so easy compared to the one in the textbook. Totally could have used it last year.


EDIT: and yup, (a+b), not (ab) :P

JC2011girl wrote: »

Oh and a quick question about P1, for Q6b ii) I got 4.5 and 2.5 when the answr was -4.5 and 2.5.. How many marks do you think I'll lose for getting the wrong sign?

At most three marks. Possibly one, depending on how you made the mistake. It's all down to how you made it in the solution and the discretion of the examiner. But it's a really, really, really small amount of marks.

buyer95

Is that a totally acceptable method?

robz18

buyer95 wrote: »

Is that a totally acceptable method?

yeah, definitely

buyer95

Colm! wrote: »

In case you can't read Slow Show's handwriting, I did up this. I've never seen the Alternate Proof before, but it's so easy compared to the one in the textbook. Totally could have used it last year.


EDIT: and yup, (a+b), not (ab) :P




What you mean a+b not(ab)

Colm!

Slow Show wrote (ab) instead of (a+b), which kind of changes an entire part of it. So I changed it back when I was typing it out.

scipsss

thats great thanks for explaining what number theorem is that ?

DessieMG

Slow Show wrote: »

Alternative (and imo, easier) version of Pythagoras:


Procrastination has reached new levels...:o and if you can't read my writing, sorry, that took a huge effort to make it as neat as it is, it's usually almost incomprehensible

EDIT: Oh jesus, that's massive...

that's what she said

Desire.

scipsss wrote: »

thats great thanks for explaining what number theorem is that ?

Number ten.

her0fire

Can anybody PLEASE explain to me what axial symmetry, central symmetry, rotatio and translations are please? Refer to 2007 P2 Q 3 b ii please! Thanks

Slow Show

Errrr I meant to say (a+b)... >.>

imtryan

Is ANYONE else doing the project maths paper

Desire.

imtryan wrote: »

Is ANYONE else doing the project maths paper

I believe Indiego is.

KaBooom

her0fire wrote: »

Can anybody PLEASE explain to me what axial symmetry, central symmetry, rotatio and translations are please? Refer to 2007 P2 Q 3 b ii please! Thanks

Axial symmetry is when an image is mirrored through an axis eg. flipped from left to right.

central symmetry is when an image is brought through 1 point so it becomes flipped up-side down.

rotation is when an image is turned by a number of degrees in a certain direction.

translation is when an image is moved a certain distance but it remains exactly the same.


In regards to the question;

A: axial symmetry
B:central symmetry
C:rotation 90 degrees clockwise.

Hope this helps, cant guarantee its all correct since this is from my own memory, and I learned it in tech graph (dont remember ever seeing this in maths!)

her0fire

KaBooom wrote: »

Axial symmetry is when an image is mirrored through an axis eg. flipped from left to right.

central symmetry is when an image is brought through 1 point so it becomes flipped up-side down.

rotation is when an image is turned by a number of degrees in a certain direction.

translation is when an image is moved a certain distance but it remains exactly the same.


In regards to the question;

A: axial symmetry
B:central symmetry
C:rotation 90 degrees clockwise.

Hope this helps, cant guarantee its all correct since this is from my own memory, and I learned it in tech graph (dont remember ever seeing this in maths!)

You won't believe how much this helped.
Thanks alot man!

KaBooom

her0fire wrote: »

You won't believe how much this helped.
Thanks alot man!

no problem bro

juncert

Thats really helpful Kaboom thanks

KaBooom

haha, no bothers, glad it helped yas out

dieselbabe

TheRedDevil10 wrote: »

These are the ones that will most likely come up

• A diagonal bisects the area of a parallelogram
• The measure of the angle at the centre of a circle is twice the measure of the angle at the circumference, standing on the same arc
• If two sides of a triangle are equal in measue, then the angles opposite thes sides are equal in measure
• The measures of the three angles in a triangle add up to 180'
• A line through the centre of a circle, perpendicular to a chord, bisects the chord

are you sure they'll come up? how do you kno?:) im completely stressing out:eek:

dieselbabe

stressing out about theorems! my teacher told me that the theorem *if two triangles are equiangular...* might come up as its the last year its in the course..i hope to god shes wrong:L

KaBooom

Join the club, im useless at the theorems and am hoping TheRedDevil is right with the theorems cuz they're the only ones im going to learn :L .. a few of them should come up since they havent been up for a few years

Desire.

dieselbabe wrote: »

stressing out about theorems! my teacher told me that the theorem *if two triangles are equiangular...* might come up as its the last year its in the course..i hope to god shes wrong:L

I think she's wrong. I mean, maybe she just made a mistake. Next year's Junior Certs will be doing the same course as us, so I doubt they would take it off in the final year?

Indiego

Desire. wrote: »

I believe Indiego is.

No, im not XD

mattol58

It really is a great day for studying those Theorems, How many marks do I need to pass Paper 2 in Maths, I'm pretty confident I did well in Paper 1, but I'm rubbish at Paper 2 and would just like to know before going in the minimum marks to get for a pass in Paper 2.

Desire.

mattol58 wrote: »

It really is a great day for studying those Theorems, How many marks do I need to pass Paper 2 in Maths, I'm pretty confident I did well in Paper 1, but I'm rubbish at Paper 2 and would just like to know before going in the minimum marks to get for a pass in Paper 2.

120 Marks.

shadowninty

Oh God this will be awful

her0fire

Any tips for question 1 ( area and volume ) guys?

juniorcertlol

need quick reply :O
can you be asked to write a formal proof on a theorem deduction :O ?

her0fire

juniorcertlol wrote: »

need quick reply :O
can you be asked to write a formal proof on a theorem deduction :O ?

No

Colm!

No. You'll be expected to know the deductions and how they work, but not asked to prove them.

her0fire

Colm! wrote: »

No. You'll be expected to know the deductions and how they work, but not asked to prove them.

What are deductions by the way?
I don't think my maths teacher told us

shadowninty

For the theorems, must we just draw the diagram and write the proof?

KatiesMusic96

imtryan wrote: »

Is ANYONE else doing the project maths paper

Yeah I am! I'm freaking out because I found the mock paper really hard, I hate project maths

Desire.

Just need a bit of clarification.

For the circumcirlce, do you bisect two angles, or two sides?

Indiego

Desire. wrote: »

Just need a bit of clarification.

For the circumcirlce, do you bisect two angles, or two sides?

For the circumcircle you bisect two sides, for the incircle you bisect two angles

Colm!

Circumcircle is bisecting lines.
Incircle is bisecting angles.
EDIT: CURSE YOU INDIEGOOOOOOOOOOOOO