!! HL Maths 2015 - predictions, guesses, Q & A, discussion ...

skippy1977

RoRo979 wrote: »

I think giving the point of the tangent may even be a bit generous. More likely question imo is what is the equation of the circle and where does the tangent intersect the line or something along those line.

Eh....this is a question taken from the Leaving Cert so I'm not sure how you can get more likely that that

Troxck

is mise spartacus wrote: »

This is a long shot but does anyone happen to have the 2015 DEB marking scheme ?

PM me your email and I'll try to send it!

Help1997

Troxck wrote: »

PM me your email and I'll try to send it!

Would it be ok if you could send me it aswell? Il pm you my email

RoRo979

skippy1977 wrote: »

Eh....this is a question taken from the Leaving Cert so I'm not sure how you can get more likely that that

damn apologies so seems very basic imo have seen much harder ones while studying befire hence why i assumed

skippy1977

RoRo979 wrote: »

damn apologies so seems very basic imo have seen much harder ones while studying befire hence why i assumed

Well actually the one you posed is a great question. Would be very challenging. The equation of a circle given two points and a tangent to that circle not at either of those points. I know it can be done but it would be long...and tricky. Must see if I can get an example and post it.

RoRo979

skippy1977 wrote: »

Well actually the one you posed is a great question. Would be very challenging. The equation of a circle given two points and a tangent to that circle not at either of those points. I know it can be done but it would be long...and tricky. Must see if I can get an example and post it.

if you do find one please do. I find the easiest way to study maths is by simple seeing how questions are done. If a question you have seen before comes up just with different numbers you then know the method to solve it I prefer studying the hardest possible stuff to come up and sure then by default your more or less studying all the other stuff, hard part is finding the weird questions because they are just that, weird and uncommon

135083

Does anyone know how you get the second value of x when solving a trig function? The question is in the 2014 sample paper, you have to solve sin2x=1/2 and they get x=pi/12 and x=5pi/12. I'm able to get the first solution just can't remember how you get the second!

skippy1977

135083 wrote: »

Does anyone know how you get the second value of x when solving a trig function? The question is in the 2014 sample paper, you have to solve sin2x=1/2 and they get x=pi/12 and x=5pi/12. I'm able to get the first solution just can't remember how you get the second!

You have to use the unit circle. I'll post solution in a bit.

135083

skippy1977 wrote: »

You have to use the unit circle. I'll post solution in a bit.

That would be great, thanks! Or tbh even if you could just talk me through the first step here I'll get it... it's weird I'm perfect at doing them when they ask you to solve an angle I was just a little thrown by having the angle as the unknown... I'm sure if I get it started the rest will follow anyway.

Edit: Nevermind, got it Was trying to subtract it from pi after dividing the angle by 2 instead of before

skippy1977

135083 wrote: »

That would be great, thanks! Or tbh even if you could just talk me through the first step here I'll get it... it's weird I'm perfect at doing them when they ask you to solve an angle I was just a little thrown by having the angle as the unknown... I'm sure if I get it started the rest will follow anyway.

Here you go, trigonometric equations have infinite solutions, so you have to look carefully at the question se see what is being looked for. For example i got 30,150...but sin 390, sin 510....also give 1/2



I see you just got it, so ignore!

numbers13

skippy1977 wrote: »

Find the equation of the circle which passes through the points a(-3,-2) and b(0,-1) and where the line 2x-y+4=0 is a tangent at the point (-3,-2)

After finding the two equations using the general equation and the slope, find the slope of the tangent. Then find the perpendicular slope (flip the slope of the tangent upside down and change the sign), with this slope and the point where the tangent intersects you can find the equation of a line through the centre. Pop (-g,-f) into that equation for your third equation.

135083

skippy1977 wrote: »

Here you go, trigonometric equations have infinite solutions, so you have to look carefully at the question se see what is being looked for. For example i got 30,150...but sin 390, sin 510....also give 1/2
]

Thanks for that! I had divided by 2 in the first step giving me the wrong reference angle so obviously the rest didn't work. It's stupid mistakes like this that will throw me off in the exam I'm sure

RoRo979

skippy1977 wrote: »

Here you go, trigonometric equations have infinite solutions, so you have to look carefully at the question se see what is being looked for. For example i got 30,150...but sin 390, sin 510....also give 1/2



I see you just got it, so ignore!

have it done nicely, dont forget however
2x = 360n
x = 180n

Kremin

Does anyone have a link to something that has ALL of inferential statistics? The folens link I have only shows confidence intervals at 95% and not the whole sample proportion thing.

skippy1977

Kremin wrote: »

Does anyone have a link to something that has ALL of inferential statistics? The folens link I have only shows confidence intervals at 95% and not the whole sample proportion thing.

Not sure if this is any good to you.
http://www.gillmacmillan.ie/AcuCustom/Sitename/DAM/058/NCPM_5_Online_Supplement.pdf

Kremin

skippy1977 wrote: »

Not sure if this is any good to you.
http://www.gillmacmillan.ie/AcuCustom/Sitename/DAM/058/NCPM_5_Online_Supplement.pdf

Could anyone tell me the difference between the two means? Some questions are throwing in two means, like x bar and mew or whatever.. Whats the difference??

lala0815

How positive are people that only theorem 11,12,13 can be asked ?

Troxck

Kremin wrote: »

Could anyone tell me the difference between the two means? Some questions are throwing in two means, like x bar and mew or whatever.. Whats the difference??

X bar is the sample mean and mew is just the mean.

Cr4pSnip3r

I don't be understanding Statistics at all.

BlueWolf16

lala0815 wrote: »

How positive are people that only theorem 11,12,13 can be asked ?

Pretty much the surest thing in the exam. Whether they actually come up or not is a different issue, but in terms of reproducing proofs, those are the only ones. Though you shouldn't ignore the others either, they might be relevant in other questions.

skippy1977

lala0815 wrote: »

How positive are people that only theorem 11,12,13 can be asked ?

It's vague. The syllabus expects you to still know anything you learned for your Junior Cert.
For the Junior Cert you were meant to know Constructions 1 to 15 and Theorems 4,6,9,14 and 19.
The Syllabus for Leaving Cert Higher Level mentions only Constructions 16 to 22 and Theorems 11,12 and 13.

It's possible. I think there would be uproar if they did ask ...say Pythagoras...but technically I believe they are entitled to...you'd need a degree in Law to look up the fine print. Sorry I know that doesn't help. I told my students to learn really well 11,12,13 especially 12 and if they had time to have a quick look over the others just in case. It's highly unlikely.

DarraghF197

Kremin wrote: »

Could anyone tell me the difference between the two means? Some questions are throwing in two means, like x bar and mew or whatever.. Whats the difference??

As Troxck said, x bar is the sample mean and mew is the population mean. It's not important to know that, as, given a normal distribution, they both equal eachother.

Ugh, doing histograms with x-intervals, finding the mean and median, just horrible. Simply horrible!

Kremin

skippy1977 wrote: »

It's vague. The syllabus expects you to still know anything you learned for your Junior Cert.
For the Junior Cert you were meant to know Constructions 1 to 15 and Theorems 4,6,9,14 and 19.
The Syllabus for Leaving Cert Higher Level mentions only Constructions 16 to 22 and Theorems 11,12 and 13.

It's possible. I think there would be uproar if they did ask ...say Pythagoras...but technically I believe they are entitled to...you'd need a degree in Law to look up the fine print. Sorry I know that doesn't help. I told my students to learn really well 11,12,13 especially 12 and if they had time to have a quick look over the others just in case. It's highly unlikely.

The syllabus says 11,12,13 are examinable but knowledge of the others is required. My taking of this is, you may need to use the theorems in a question but not prove them.

135083

Kremin wrote: »

Could anyone tell me the difference between the two means? Some questions are throwing in two means, like x bar and mew or whatever.. Whats the difference??

xbar (anything with bar my teacher told me) is a parameter (describing sample). Mu is a statistic (describes population). Thanks to the central limits theorem we often use xbar to *infer* what mu can be, plus or minus the error, giving us a confidence interval that mu is 95% certain within.

Kremin

DarraghF197 wrote: »

As Troxck said, x bar is the sample mean and mew is the population mean. It's not important to know that, as, given a normal distribution, they both equal eachother.

Ugh, doing histograms with x-intervals, finding the mean and median, just horrible. Simply horrible!

im dreading a 50marker on this, better root out the auld debs mock and attempt the question. everyone got 0 on it in the mocks because we hadn't even done it yet

skippy1977

Kremin wrote: »

The syllabus says 11,12,13 are examinable but knowledge of the others is required. My taking of this is, you may need to use the theorems in a question but not prove them.

I'd agree. The syllabus says "A knowledge of the Axioms, concepts, Theorems and Corollaries prescribed for JC-HL will be assumed." but doesn't mention specifically proving them.

The only thing that threw me was Examcraft putting a JC one on their Mock. Not that this means anything.

simplyno1

Kremin wrote: »

im dreading a 50marker on this, better root out the auld debs mock and attempt the question. everyone got 0 on it in the mocks because we hadn't even done it yet

If you are worrying about statistics, or anyone else for that matter, just go over the folens handout (if you have it) which explains confidence interval, null hypothesis and the new statistics like calculating margin of error etc. I did that and got a fairly good understanding of it all.

Then you should attempt these questions:

(www(DOT)studyclix(DOT)ie/Subjects/Leaving-Certificate/Higher/Mathematics/Statistics-_and_-Data).

I have a great grasp on stats now... can't wait for that 50 marker!

135083

skippy1977 wrote: »

I'd agree. The syllabus says "A knowledge of the Axioms, concepts, Theorems and Corollaries prescribed for JC-HL will be assumed." but doesn't mention specifically proving them.

The only thing that threw me was Examcraft putting a JC one on their Mock. Not that this means anything.

Yeah and also, while I know you go based on the syllabus and not the text book, ours specifically says that formal proofs can only be asked for 11-13 whereas the rest can be applied in questions.

Troxck

Kremin wrote: »

im dreading a 50marker on this, better root out the auld debs mock and attempt the question. everyone got 0 on it in the mocks because we hadn't even done it yet

It isn't THAT bad! I just wish we could still use the formulae my class learnt last year. I've done the 2015 samples and redid the Mock question so hopefully something similar to that comes up!

tornados2111

Kremin wrote: »

Could anyone tell me the difference between the two means? Some questions are throwing in two means, like x bar and mew or whatever.. Whats the difference??

as far as I understand, xbar is always to do with the sample. Remember, the sample is always measured relative to the actual mean, which we represent by mew