Maths P. 2 Pythageros Theorem

sotisme

Hi

Please can people tell me:

Is it really true that the square method of proving pythagerous theorem won't be accepted by the SEC if it comes up?

Has anyone else just been taught this method?!

Any reply is greatly appreciated

Thanks

DublinArnie

sotisme wrote: »

Hi

Please can people tell me:

Is it really true that the square method of proving pythagerous theorem won't be accepted by the SEC if it comes up?

Has anyone else just been taught this method?!

Any reply is greatly appreciated

Thanks

Hypotenus^2 = a^2 + b^2????

I learnt the therom where you draw three more identical triangles to form a diamond in the middle. The proof is easy .

abcdefghijkl

DublinArnie wrote: »

Hypotenus^2 = a^2 + b^2????

I learnt the therom where you draw three more identical triangles to form a diamond in the middle. The proof is easy .

Haven't heard of that one. There are a few proofs for the Pythagoras Theorem. Wish it was clear which one is needed.

sotisme

DublinArnie wrote: »

Hypotenus^2 = a^2 + b^2????

I learnt the therom where you draw three more identical triangles to form a diamond in the middle. The proof is easy .

Yeah thats the one I learned as well!

Rumour has it that it isn't accepted by the SEC !

onlinenerd

Yeah the square one wont be accepted as my teacher mailed them to which they replied a NO so the triangle one was taught

abcdefghijkl

Is it the similar triangles one they accept?

Cr4pSnip3r

abcdefghijkl wrote: »

Is it the similar triangles one they accept?

Well, halphabet, the one I got is where you split a triangle and separate the second smaller triangle from the larger one, so you have the similar triangles. So, yes, that's it.

abcdefghijkl

Yeah, that's the one I know. Thanks.

glitzandbits

sotisme wrote: »

Hi

Please can people tell me:

Is it really true that the square method of proving pythagerous theorem won't be accepted by the SEC if it comes up?

Has anyone else just been taught this method?!

Any reply is greatly appreciated

Thanks

The only one I ever learned was one with four right angled triangles to make a big square with a small square inside??

DublinArnie

Cr4pSnip3r wrote: »

Well, halphabet, the one I got is where you split a triangle and separate the second smaller triangle from the larger one, so you have the similar triangles. So, yes, that's it.

We never learnt that way! :eek: Care to share?

abcdefghijkl

DublinArnie wrote: »

We never learnt that way! :eek: Care to share?

Here's a link to a video I found:
https://www.khanacademy.org/math/geometry/right_triangles_topic/pythagorean_proofs/v/pythagorean-theorem-proof-using-similarity

It seems a bit complex at first, and he rambles a lot, but if you focus you should understand it.

MmmPancakes

This way is acceptable


Not this

sotisme

MmmPancakes wrote: »

This way is acceptable


Not this

What? my whole year has learnt the second one as well as friends in other schools! Are you sure??

And do you know how many marks you would lose for doing the 2nd theorem?

Thanks

MmmPancakes

sotisme wrote: »

What? my whole year has learnt the second one as well as friends in other schools! Are you sure??

And do you know how many marks you would lose for doing the 2nd theorem?

Thanks

According to a source from above, the second one is not accepted. Email the SEC quick and ask, but apparently they said no. You'd lose all them probably.

Project maths and **** they want you to use similar triangles and all that ****e

positivealf

omg what the hell, why didnt my math teacher tell us? we only learned the theorem, we didnt learn any proofs or anything like that. Or is this only for HL math paper2? If i were to make a proof i would draw a triangle enclosed with 3 squares and 2 of the a^2+b^2= c^2 is that ok?

spurious

Click on Theorem 14 in this link.
http://resources.teachnet.ie/hpunzet/2010/jch_theorems.html

It is the 'preferred' method.

sotisme

spurious wrote: »

Click on Theorem 14 in this link.
http://resources.teachnet.ie/hpunzet/2010/jch_theorems.html

It is the 'preferred' method.

The link won't open for me
Does it say if the other method is acceptable?
Thanks

DublinArnie

spurious wrote: »

Click on Theorem 14 in this link.
http://resources.teachnet.ie/hpunzet/2010/jch_theorems.html

It is the 'preferred' method.

Thanks!

sotisme

DublinArnie wrote: »

Thanks!

It won't load for me, does it say that pur method is okay?!

DublinArnie

sotisme wrote: »

It won't load for me, does it say that pur method is okay?!

It doesn't say anything relating to the method I learnt, it just shows the theroms and proofs. Therom 14 is with two triangles, a small and big one ..

doyle97

I'm genuinely refusing to believe that the square diagram method is not accepted..if it was not accepted why would all the higher level maths teachers in my school teach it? why would other schools teach it? I did it in my mocks and got full marks..so I'm going to continue using it. Also if it isnt accepted (which i highly doubt) it would be extremely lousy of the sec and would in return look bad on them..

spurious

Hmmm. Not sure why it isn't opening. It opens in a pop-up and I'm using Firefox if that makes a difference. Essentially it's comparing two triangles.

Does this work?
http://resources.teachnet.ie/hpunzet/2010/files/theorem14st.html

Keep pressing the arrow for the next line.

S_Barry3011

I would say they won't put Theorem 14 on the exam to avoid the confusion/complaints

MmmPancakes

doyle97 wrote: »

I'm genuinely refusing to believe that the square diagram method is not accepted..if it was not accepted why would all the higher level maths teachers in my school teach it? why would other schools teach it? I did it in my mocks and got full marks..so I'm going to continue using it. Also if it isnt accepted (which i highly doubt) it would be extremely lousy of the sec and would in return look bad on them..

It really wouldn't. For those sitting project maths, you know how everything has changed, they want to focus on you understanding, rather than just parroting off a proof. That's why it's like this for this theorem imo, it refers to similar triangles ((important in project maths) and requires you to know what you're doing because it's longer. So yes, you have to understand it. I don't see the problem, just go and study this theorem without the square method and make sure you understand it, and do it in the exam. No point in refusing to do it, if it's not accepted, tough luck, there goes 20 marks.

sotisme

MmmPancakes wrote: »

It really wouldn't. For those sitting project maths, you know how everything has changed, they want to focus on you understanding, rather than just parroting off a proof. That's why it's like this for this theorem imo, it refers to similar triangles ((important in project maths) and requires you to know what you're doing because it's longer. So yes, you have to understand it. I don't see the problem, just go and study this theorem without the square method and make sure you understand it, and do it in the exam. No point in refusing to do it, if it's not accepted, tough luck, there goes 20 marks.

My theorem involves congruent triangles which are equally as important
Literally everyone I know from various schools is learning the box one so I think I'll chance it!

doyle97

MmmPancakes wrote: »

It really wouldn't. For those sitting project maths, you know how everything has changed, they want to focus on you understanding, rather than just parroting off a proof. That's why it's like this for this theorem imo, it refers to similar triangles ((important in project maths) and requires you to know what you're doing because it's longer. So yes, you have to understand it. I don't see the problem, just go and study this theorem without the square method and make sure you understand it, and do it in the exam. No point in refusing to do it, if it's not accepted, tough luck, there goes 20 marks.

but in fairness, why are our teachers being taught to teach it this way if it is incorrect? surely someone from the department of education would have notified us months ago..

MmmPancakes

doyle97 wrote: »

but in fairness, why are our teachers being taught to teach it this way if it is incorrect? surely someone from the department of education would have notified us months ago..

Maybe they haven't been told, or didn't attend inservices where it may have been mentioned. I'm not sure but I'd learn the new way if I were you, we learned it this way and it's easy to recall once you can understand similar triangles

sotisme

MmmPancakes wrote: »

Maybe they haven't been told, or didn't attend inservices where it may have been mentioned. I'm not sure but I'd learn the new way if I were you, we learned it this way and it's easy to recall once you can understand similar triangles

There is no reason why our proof is unacceptable, the syllabus requires us to be able to prove the theorum. Once we can prove it I don't see how we prove it to matter. Anyways they're hardly going to let half the country lose 20 marks because they didn't specify that we had to learn it a particular way

spurious

As long as they didn't specify. I'm checking circulars.

Meanwhile, here's a screenshot of that proof.

Mary A

p t equals h2=x2+y2 simple

whiteandlight

I've taught in a pilot school for two years and a main stream school now for two years. The box proof is definitely not acceptable. Your theorems should have been taught and built in order of the syllabus and you have not done congruency or the theorem related to area of a triangle before Pythagoras.

I have been told this definitevely at inservice in both the pilot school and main schools. We weren't happy about it but I can see their logic. You should have learnt the proof before congruency so why would you go back and teach a different proof?

Finally pretty sure the box proof is not in any books, nor is it anywhere on projectmaths.ie and the proof spurious has linked above is written out in the geometry appendix to the syllabus so I cannot see them accepting any other proof.


My advice would be to go over the one above and forget the box proof. If you need help just ask

Pegasusbridge

Musicmental85 wrote: »

I've taught in a pilot school for two years and a main stream school now for two years. The box proof is definitely not acceptable. Your theorems should have been taught and built in order of the syllabus and you have not done congruency or the theorem related to area of a triangle before Pythagoras.

I have been told this definitevely at inservice in both the pilot school and main schools. We weren't happy about it but I can see their logic. You should have learnt the proof before congruency so why would you go back and teach a different proof?

Finally pretty sure the box proof is not in any books, nor is it anywhere on projectmaths.ie and the proof spurious has linked above is written out in the geometry appendix to the syllabus so I cannot see them accepting any other proof.


My advice would be to go over the one above and forget the box proof. If you need help just ask

I was told at inservice that it was acceptable but of course inservice is not run by the sec. The reason for it not being acceptable makes no sense. Congruency is listed as an axiom and therefore comes before any proof of theorems in the syllabus. The area formula is in the tables and to the best of my knowledge there is no requirement to teach all strand two before area in strand 3. To disallow a perfectly valid way of proving pythagoras based on an axiom of the course would seem to go against the whole idea of project maths.

whiteandlight

Whether or not it is acceptable is a thread of its own to be fair to the JC students. Personally I don't mind if it is on or off but it would seriously have helped if they had actually told everyone one way or another, particularly since we seem to have gotten two different answers at inservice!

I would have to advise using the one that is actually in the syllabus rather than one that is not (box proof)

sotisme

Musicmental85 wrote: »

I've taught in a pilot school for two years and a main stream school now for two years. The box proof is definitely not acceptable. Your theorems should have been taught and built in order of the syllabus and you have not done congruency or the theorem related to area of a triangle before Pythagoras.

I have been told this definitevely at inservice in both the pilot school and main schools. We weren't happy about it but I can see their logic. You should have learnt the proof before congruency so why would you go back and teach a different proof?

Finally pretty sure the box proof is not in any books, nor is it anywhere on projectmaths.ie and the proof spurious has linked above is written out in the geometry appendix to the syllabus so I cannot see them accepting any other proof.


My advice would be to go over the one above and forget the box proof. If you need help just ask

Every student I know (from various schools) is doing the box theorem and When you put together everyone in their years hundreds of students have only learnt the box theorem. The schools I'm talking about are very well known. Will they really refuse to mark mine if I give the box theorem?

Also my maths book is a project maths book containing the box theorem!

spurious

They won't refuse to mark it.


What will probably happen is that some centres will have the 'right' proof and so many will have the 'unacceptable' one that they will have to change the marking scheme to allow it and send a strongly worded circular to schools telling the teachers to do what they are told.

whiteandlight

spurious wrote: »

They won't refuse to mark it.


What will probably happen is that some centres will have the 'right' proof and so many will have the 'unacceptable' one that they will have to change the marking scheme to allow it and send a strongly worded circular to schools telling the teachers to do what they are told.

This is what I would expect if the numbers are this high. Having said that maybe they changed their mind-its hard to tell with Project Maths

Leopard_Star

ive never heard of anything about proving things using squares and triangles.does this only apply to higher maths?

positivealf

PREDICTIONS FOR CONSTRUCTIONS THAT MAY COME UP IN MATH PAPER OL 2013 G0DDAMNIT!

Jijsaw

positivealf wrote: »

PREDICTIONS FOR CONSTRUCTIONS THAT MAY COME UP IN MATH PAPER OL 2013 G0DDAMNIT!

The majority of us on here do HL, sorry

DublinArnie

positivealf wrote: »

PREDICTIONS FOR CONSTRUCTIONS THAT MAY COME UP IN MATH PAPER OL 2013 G0DDAMNIT!

*laughs* So funny Albert!

S_Barry3011

Well I was right