Higher Maths, Paper Two

DS

Originally posted by Mutant_Fruit
-proof of difference equations formula

is that the same as Q7 (B) (i) in 1994? is that they way you'll be asked to prove it?

Yeah that's the one. We could be up for a 10 year anniversary

Which ones are those?

The first 12. The sine and cosine rules, and then the first 5 from the left and right columns i.e. cos(A+B) to (cosA)^2 and then cos2A to (sinA)^2

subway_ie

Originally posted by Discharger Snake
The first 12. The sine and cosine rules, and then the first 5 from the left and right columns i.e. cos(A+B) to (cosA)^2 and then cos2A to (sinA)^2

Just went looking for a log book to see which ones you were talking about... somehow I've managed to take two log books from the exam centre. Dunno how the feck that happened. :dunno:

Do we have to be able to prove the Sine rule as well as the cosine rules? I don't remember ever doing that?

Time Magazine

I don't think the sine rule is on the course. Cosine is definitely. I'm almost sure sine rule isn't though. Is there an example in the papers of the maclaurin series you said?

subway_ie

Originally posted by Angry Banana
Is there an example in the papers of the maclaurin series you said?

I'm not too sure about the actual papers, but if you have the "Less Stress More Success" revision book then it's in there somewhere near the end of the Maclaurin section. Just remember, it's only a guess that something like that will come up. Don't bother trying to learn it off or anything, just revise over it.

DS

Sorry you're right sine rule doesn't have to be proved. You have to prove (sinA)^2 + (cosA)^2 = 1, that's what I left out instead of sine rule.

Mutant_Fruit

1999 Paper2, Question 7 C.

Its easy, i know it is, but i can't get the feckin thing to work out.

I worked out the b in terms of a to be 4a/5

i worked out standard deviation to be sq_rt[( 61a^2)/25]

I;m resonably certain the standard deviation is wrong, bt for the life of me i cna;t find the mistake.

claire h

It's the sq_rt[(74a^2)/100], or (root74)(a)/10.

The four yokes you add together after taking away the mean from the original numbers are -3a/5, 7a/5, -4a/5, and 0, and then dividing by four. Probably just a sign mistake or something.

subway_ie

Originally posted by Mutant_Fruit
1999 Paper2, Question 7 C.

I can scan in a solution if you want, but like Claire H says, it's probably just a sign error.

Mutant_Fruit

-4a/5???

I got -8a/5.

B= 4a/5, the mean is 8a/5.

Therefore isnt the third figure going to end up being -b, which is -8a/5...

a solution would be nice

subway_ie

Quality isn't great, but you should be able to make it out:

claire h

Originally posted by Mutant_Fruit
-4a/5???

I got -8a/5.

B= 4a/5, the mean is 8a/5.

Therefore isnt the third figure going to end up being -b, which is -8a/5...

a solution would be nice

b (original figure) - 2b (mean) = -b
4a/5 - 8a/5 = -4a/5

Look, reread what you've written. You have b = 4a/5, -b must therefore be -4a/5, not -8a/5.

eta: ah, nevermind, you have the solution now anyway.

Mutant_Fruit

i made a rediculous mistake when i was doing it. at least it was only a 3 mark mistake.

DS

I've done everything now apart from the pg 9 proofs. It's gonna be a struggle to force myself through them, firstly because 4 and 5 are my fallback Q's, secondly because my ****ing wisdom tooth decided to go mental on me and now I can barely eat, never mind concentrate at a desk. I'm on the nurofen and antibiotics and tincture of mirrh and whatever else you can think of. Great how the immune system tends to go to sleep at times like this.

subway_ie

Wisdom teeth are weapons of satan. I was in agony during the orals with mine. Totally fecked up my french because of that and a hugeeee migraine. Luckily I've relaxed a bit since then...
The only question I'm worried about right now is the line. Maybe the circle aswell. Not so much because they're hard, but they're so damn long sometimes. The trig proofs aren't hugely imortant - as long as you have a rough idea you'll figure it out in the exam. Just did 5 paper twos today. Lookin forward to tomorrow.

DS

Maybe do 6 and 7 first, then you'll feel like you have all day for the circle and the line, which are by far the longest. Might do that myself actually. Although I'll be a bit jittery on the first Q, so probability probably wouldn't be the best for that, best with something more formulaic. Like the circle. *sigh* :rolleyes:

subway_ie

Originally posted by Discharger Snake
Maybe do 6 and 7 first, then you'll feel like you have all day for the circle and the line

:dunno: Haven't even looked at probability/statistics since we did it in 4th year. Even then I didn't really look at them properly. Plus at least with the circle and line you have a rough idea whether your answer's right. They might be long, but at least they're predictable and (semi) easy.

oeNeo

For anyone doing question 8, any tips on how to do the general test ratios? The second parts on the Maclaurin series.

Our teacher did one class on this and absolutely no-one knew what she was doing.

"Write down the general term and use the Ratio Test to show that the series converges for all x E R"

(The one I'm looking at is 2001 B ii)

Mutant_Fruit

Basically, once you write down the terms up to the one including x^7, you will see a pattern in the way the numbers increase.

You then have to think, and write up something in a general way, that will represent any term in the sequence by only having to substite in a letter. just like the Un of a series.

if i write 1 + x + x^2 + x^3 and ask you to write out the general term, youd write x^(n-1). That way, when you put in 1, you get x^0, which is 1 (the first term), when you put in 2 you get x (the second term) etc

You just do that for the series.

Then, when you have Un, you just substitute in "n+1" for N, to get U(n+1) and then divide U(n+1) by Un and get the lim as n -> infinity. You should get a number like 1/2 or 2 or something like that.

Very easy once you do one or two.

PrecariousNuts

Deffo no 6 or 7 for me, I'm going to rip through the circle, then the line, vectors and hopefully the trig won't be a complete ass of a question. The one thing trig has going for it is that most of the part c's are just one liners like prove sin(A+B) blah. Q8 should be easy too, ratio test as an entire part c lol

oeNeo

Hm, sounds pretty doable actually. My maths teacher was babbling on for ages about all sorts of stuff, but you seemed to have put it nice and simple. Cudos to you.

Mutant_Fruit

i do my best. Good luck tomorrow, hopefully what i've said helps.

subway_ie

Isn't it great how boards.ie has mastered time travel, and can now transport itself back to 3am this morning? If only I could do it. Could've fixed my maths paper.

seamus

Originally posted by subway_ie
Isn't it great how boards.ie has mastered time travel, and can now transport itself back to 3am this morning? If only I could do it. Could've fixed my maths paper.

I have absolutely nothing to show for my day in work today