**HL Maths Paper 2 before/after**

no scope codgod

Ye I'm fairly sure that the only criterion is that the angles are all 90

Kingkumar

Raeral wrote: »

A square is a form of rectangle though

really didnt know..... well i wasted all that time trying to prove the lengths are different..:mad: and failing

suitcasepink

This is probably ridiculous.. But I said how a rectangle is symmetrical, then I used the 2 triangles inside and proved them to be congruent.. So the triangles were the same as each other so the shape was a rectangle...

It sounds even stupider writing it now than it did the first time >.<

sganyfx

What did people get for the co-ordinates of the point of intersection of the circles?

jamo2oo9

sganyfx wrote: »

What did people get for the co-ordinates of the point of intersection of the circles?

I got (-1.4,-08) I think or it could be the other way round.
What did you get?

ahmdoda

im suprised the sin rule proof came up didnt expect that any one forgot to do the obtuse angle case?

no scope codgod

ahmdoda wrote: »

im suprised the sin rule proof came up didnt expect that any one forgot to do the obtuse angle case?

Why would you have to do the obtuse case as well? Surely if they don't ask for it you only have to do one or the other?

sganyfx

jamo2oo9 wrote: »

I got (-1.4,-08) I think or it could be the other way round.
What did you get?

Something similar. and the slope of the tangent was -4/3 or something like that yeah?

sganyfx

ahmdoda wrote: »

im suprised the sin rule proof came up didnt expect that any one forgot to do the obtuse angle case?

Only one is necessary I do believe

Raeral

no scope codgod wrote: »

Why would you have to do the obtuse case as well? Surely if they don't ask for it you only have to do one or the other?

For proving the sine rule that didn't specify any kind of triangle so you had to prove both the acute case and the obtuse case, unless you used the area formula to prove it. I believe you're thinking about later on when they asked you to find area of the acute angled triangle.

Raeral

deise_girl wrote: »

This is probably ridiculous.. But I said how a rectangle is symmetrical, then I used the 2 triangles inside and proved them to be congruent.. So the triangles were the same as each other so the shape was a rectangle...

It sounds even stupider writing it now than it did the first time >.<

Unfortunately, if you did correctly prove their congruency, it still only proves that it's a parallelogram and not an actual rectangle

jamo2oo9

sganyfx wrote: »

Something similar. and the slope of the tangent was -4/3 or something like that yeah?

Yeah that what I got too. Grand on that question now

diarmo06

Has to be said, maths overall was a lovely paper for those, of whom I am one, that were looking for a lovely sneaking D2/3. Thunderous parts on both papers for those looking anywhere above a B1.

Happy days for the minnows! :P

no scope codgod

Raeral wrote: »

For proving the sine rule that didn't specify any kind of triangle so you had to prove both the acute case and the obtuse case, unless you used the area formula to prove it. I believe you're thinking about later on when they asked you to find area of the acute angled triangle.

I'm fairly certain you don't have to prove it for the obtuse case as well. My Textbook (Texts and Tests) doesn't even make reference to the obtuse case at all.

bpb101

yea went well myself.
Had looked over how to prove the sin rule last night, was actualy amazed that it came up. Fairly happy with it, Paper 1 was hard ennough

LC 2013 SURVIVOR

Raeral wrote: »

All in all, not too bad. Managed to answer everything anyway coincidentally, I happened to do a project on the arbelos for the young scientists in TY, never in my wildest dreams did I actually think it would turn up on the exam :P

Also did anyone else spot a problem with the triangle they gave you in question 8. It was supposed to have sides of 80 and 110 with an enclosed angle of 124 degrees and another angle of 36. However this triangle doesn't exist as 80/sin20 isn't equal to 110/sin36

I saw that aswell but just went with it and got a very weird answer, like 136 for the other angle and just accepted it

sganyfx

Any idea when the paper will be uploaded?

no scope codgod

sganyfx wrote: »

Any idea when the paper will be uploaded?

I'd say they'll upload it with Irish in one go, so probably around 5 if I had to guess.

peekachoo

For a person that's shoite at maths, i found that surprisingly okay!
Now the question 9 area question was a complete joke i couldn't get my head around it at all!
But the trig was relatively okay and there was nothing too tricky in the stat/prob side of things.

Actually for the question about changing the deviation of plants with added hormones? What was i supposed to do there? :eek:

RML

Anyone found the solutions for Paper 2?

RML

Man.UnitedLad wrote: »

Yanno in the line question? Was l an answer 3 times?!

Thank God, I got the same thing too!!

curly135

Wasn't expecting that Altough to be fair it wasn't a bad paper in it's own right, I just got caught off guard a bit.... sadly my A1 chances may not be so good now xD

Strangely enough I found Q.9 to be quite easy apart from one or two bits... I completely screwed up Q.4, couldn't get the common point and tangent, and Q.5 didn't go so well either... but all in all, not too bad

sganyfx

RML wrote: »

Thank God, I got the same thing too!!

Could you please write what you put down I for?

SecondMan

Actually so pissed off with paper. My head wasn't focused at all. Ah well.

RML

Umm I dont remember that well.. All I know is that I had L 3 times in the grid.

valencianista

Did anybody else think there was a problem with Q8? 80/sin20 and 110/sin36 do not equal!! Also if you divide it into two triangles and get the cos80=a and cos110=a and add them together you dont get the same answer that you did with the sin rule! Surely there was a mistake in that! Or am i just crazy?

D_s

Scariest moment of my life when 30 seconds before walking into the exam hall realise my pencil case containing my calculator fell out of my bag in the car! :eek:

Panicking so bad, saw my maths teacher walking down the corridor and started shouting "Sir! Sir! My Pencil case! Gone! AAAH!" :P He gave me 3 pens and a calculator, saved my life.

For the crop graphs, I got the first one as being shifted to the right, the second one was skinnier but taller, and the 3rd one was fatter but shorter. I only had one shot at them seeing as I didn't have a rubber, and I forgot to make them taller and shorter, just skinnier and fatter Couldn't change it once I saw my mistake.

Rest of the paper was alright though, trickier than paper 1 granted. Was delighted when Sine rule proof came up, literally the only proof I know :pac:

ahmdoda

valencianista wrote: »

Did anybody else think there was a problem with Q8? 80/sin20 and 110/sin36 do not equal!! Also if you divide it into two triangles and get the cos80=a and cos110=a and add them together you dont get the same answer that you did with the sin rule! Surely there was a mistake in that! Or am i just crazy?

yes so i assumed they were not looking for the perpindular distance and used the cosine rule to work out the answer

Chikablam

Differentiation on Paper 2? The ****?

RML

Chikablam wrote: »

Differentiation on Paper 2? The ****?

Umm Differentiation?? Are you sure?

LC 2013 SURVIVOR

valencianista wrote: »

Did anybody else think there was a problem with Q8? 80/sin20 and 110/sin36 do not equal!! Also if you divide it into two triangles and get the cos80=a and cos110=a and add them together you dont get the same answer that you did with the sin rule! Surely there was a mistake in that! Or am i just crazy?

they made a mistake by making a triangle that cant exist. here have some free marks

Chikablam

RML wrote: »

Umm Differentiation?? Are you sure?

Yeah, last question, find the maximum are of the whatever it's called

D_s

RML wrote: »

Umm Differentiation?? Are you sure?

Yeah the max. area of the arbelos was Da/dx = 0

LC 2013 SURVIVOR

D_s wrote: »

Yeah the max. area of the arbelos was Da/dx = 0

you cant be asked calculus anywhere except for section C paper 2. -the syllabus

RML

:eek:
Totally failed that question. Didn't even realise there was differentiation..

no scope codgod

LC 2013 SURVIVOR wrote: »

you cant be asked calculus anywhere except for section C paper 2. -the syllabus

You probably didn't have to use differentiation, it just made it easier

Copper_pipe

LC 2013 SURVIVOR wrote: »

they made a mistake by making a triangle that cant exist. here have some free marks

Are you sure they made a mistake?

LC 2013 SURVIVOR

Copper_pipe wrote: »

Are you sure they made a mistake?

ya the basic rules of a triangle were not met in the question. either that or a lot of people made the same mistake. however i checked with a few A1 students and my teacher after the test and we agreed we had some free marks

Chikablam

LC 2013 SURVIVOR wrote: »

they made a mistake by making a triangle that cant exist. here have some free marks

0___0

D_s

LC 2013 SURVIVOR wrote: »

you cant be asked calculus anywhere except for section C paper 2. -the syllabus

no scope codgod wrote: »

You probably didn't have to use differentiation, it just made it easier

Yeah I'd say this is the case. What other method did people use? Just curious. I suppose you could recognise that the pattern for area is a quadratic with a vertex at 9Pi or whatever.

You wouldn't lose mark for doing differetiation though would you?

LC 2013 SURVIVOR

D_s wrote: »

Yeah I'd say this is the case. What other method did people use? Just curious. I suppose you could recognise that the pattern for area is a quadratic with a vertex at 9Pi or whatever.

You wouldn't lose mark for doing differetiation though would you?

id say that the project maths did that on purpose. they will definitely reward full marks if your method gave you the right answer

Copper_pipe

LC 2013 SURVIVOR wrote: »

ya the basic rules of a triangle were not met in the question. either that or a lot of people made the same mistake. however i checked with a few A1 students and my teacher after the test and we agreed we had some free marks

only if you attempted it I presume ?

no scope codgod

D_s wrote: »

Yeah I'd say this is the case. What other method did people use? Just curious. I suppose you could recognise that the pattern for area is a quadratic with a vertex at 9Pi or whatever.

You wouldn't lose mark for doing differetiation though would you?

I suppose you could have graphed it and just found the maximum point, or else used trial and error until you found it. And no they can't take marks off if it's a valid method.

LC 2013 SURVIVOR

Copper_pipe wrote: »

only if you attempted it I presume ?

The first rule of HL maths with project maths is that you will be given marks for almost anything! drawing a triangle would have probably yielded marks

Eurovisionmad

Thought it was grand, easy out but a bit light on eh ………maths :L

Guys, what chapter was question 9? I couldn't attempt any of it. It had my brain fried! Otherwise, I think I got full marks in other sections.

Eurovisionmad

LC 2013 SURVIVOR wrote: »

id say that the project maths did that on purpose. they will definitely reward full marks if your method gave you the right answer

The marking scheme will always say "Methods are not exhaustive, if its a valid method and you get the right answer they can't not give the marks!

no scope codgod

Deleted User wrote: »

Guys, what chapter was question 9? I couldn't attempt any of it. It had my brain fried! Otherwise, I think I got full marks in other sections.

There's no real chapter. It drew on parts of the theorems as well as a bit of circle theory and some trig at the start as well. Some calculus too for finding the max area.

RML

How will we officially know that they made a mistake and we get free marks??

no scope codgod

no scope codgod wrote: »

There's no real chapter. It drew on parts of the theorems as well as a bit of circle theory and some trig at the start as well. Some calculus too for finding the max area.

Well I attempted it but it was awful I feel.