Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

Definitive list of proofs for HL Maths PII

Options
  • 06-06-2009 11:51pm
    #1
    Registered Users Posts: 549 ✭✭✭


    OK, here's what I have, please let me know what proofs are missing:


    1. Equation of a tangent to a circle
    The equation of the tangent to the circle x^2 + y^2 = r^2 at the point (x1, y1) on the circle is: x1.x + y1.y = r^2


    2. Angle between two lines
    If θ is the angle between two lines with slopes m1 and m2, then:
    tanθ = (m1-m2)/(1+ m1.m2)

    3. Cos (A+B)
    Cos(A + B) = CosA.CosB - SinA.SinB

    4. Perpendicular distance from a point to a line
    The perpendicular distance, d, from the point (x1, y1) to the line ax + by + c = 0 is given by:
    |ax1 + by1 + c| / sq.rt(a^2 + b^2)

    5. Difference equations theorem
    If α and β are the roots of the quadratic equation px^2 + qx + 2 = 0 and Un = lα^n + mβ^n for all n, then:
    pun+2 + qun+1 + run = 0 for all n

    6. Cosine Rule
    In triangle abc, a^2 = b^2 + c^2 - 2bc.CosA


    Then there are a load of possible Trig proofs. I THINK most of these can be answered just using and manipulating information from the log tables.

    Please add any I've forgotten


«1

Comments

  • Closed Accounts Posts: 456 ✭✭aine-maire


    Thank GOD the perpendicular distance proof came up last year!


    I know that doesn't help formulate your list,but it does make it a little shorter;)


  • Registered Users Posts: 313 ✭✭HQvhs


    There are few semi-proofs in co-ordinate geometry. Proving a line segment is mapped onto another line segment and the like.


  • Closed Accounts Posts: 407 ✭✭OxfordComma


    Yeah, I agree about the line... There's 2 or 3 proofs involving transformations.

    You have to be able to use the cos(A-B) formula to get sin(A+/-B) and tan(A+/B)... you also have to be able to get the formula for sin^2A and cos^2A as far as I know...


    Do the Maclaurin series in further calculus count as proofs? Probably not.


  • Registered Users Posts: 4,227 ✭✭✭awhir


    anyone have a list of all the smaller proofs for example the tan(a+b)


  • Closed Accounts Posts: 2,026 ✭✭✭Killaqueen!!!


    The PIL formula, Tangent theorem AND cosine rule all came up last year.
    So hopefully that will eliminate them from coming up this year. I bet they'll be mean and put one of the above on it again!


  • Advertisement
  • Closed Accounts Posts: 5,109 ✭✭✭QueenOfLeon


    Theres 4 line translations/proofs.

    Theres a Line proof about 3 concurrent lines.

    For some reason, i have the area proof (half abSinC) and the Sine formula (Sin A/a = Sin B/b) written out from ages ago....do we need to know these?

    Its worth knowing that the (Cos squared A + Sine squared A = 1) formula uses the unit circle.

    Tan (A+B) proof has a tricky bit in it that would probably be worth learning off.

    These aren't proofs, but the (Cos(90 - A) = Sin A) things are handy.


    Thats all i think!


  • Registered Users Posts: 549 ✭✭✭Jam-Fly


    out of interest, if you are prepared for nine questions, would it be possible to avoid doing any proof? I assume it wud be..


  • Registered Users Posts: 1,082 ✭✭✭Fringe


    Shame that a few proofs aren't coming up since a lot came up last year. There were barely on Paper 1 this year so I'm hoping some proofs come up. They're so easy once you know how to do it!


  • Closed Accounts Posts: 28 doorknob_opener


    awhir wrote: »
    anyone have a list of all the smaller proofs for example the tan(a+b)


    Just listing them ...might take a while ...come back in 10 mins ...


  • Closed Accounts Posts: 5,857 ✭✭✭professore


    I think regurgitating proofs in an exam is a completely useless exercise from the point of view of testing mathematical ability. But that's the dumb system we are stuck with. Good luck with the exam.


  • Advertisement
  • Closed Accounts Posts: 5,082 ✭✭✭Pygmalion


    Jam-Fly wrote: »
    out of interest, if you are prepared for nine questions, would it be possible to avoid doing any proof? I assume it wud be..
    You probably could avoid them, but there's no guarantee that there'll be no proofs you'll have to do, just very, very unlikely.

    If you really want to ace it learn the proofs that might come up on just one or two questions.


  • Registered Users Posts: 2,365 ✭✭✭spoonbadger


    If you think of the maclaurin series as proofs, then there's about 6 of those.

    Even if you dont, it still doesn't hurt to learn the dividing idea in the tan-1 one.


  • Closed Accounts Posts: 28 doorknob_opener


    awhir wrote: »
    anyone have a list of all the smaller proofs for example the tan(a+b)

    I tried making it look ''mathsy'', you know with fractions ect..., but the usual mathods I use on a different forum didn't work :(. Since I can't make powers, ^2 means to the powers of 2. And to make it clear, all angles are in brackets.

    1. cos^2(A) + sin^(2) = 1

    2. Cosine formula a^2 = b^2 + c^2 - 2bc cos(A)

    3. cos(A+B) = cos(A)cos(B) - sin(A)sin(B)

    4. cos(2A) = cos^2(A) - sin^2(A)

    5. sin(A+B) = sin(A)cos(B) + cos(A)sin(B)

    6. sin(2A) = 2sin(A)cos(A)

    This is where this might get hard to understand. By / I mean a fraction

    7. tan(A+B) = [tan(A) + tan (B)]/[1 - tan^2(A)]

    8. tan2A = [2tanA]/[1 - tan^2(A)]

    9. cos2A = [1 - tan^2(A)]/[1 + tan^2(A)]

    10. sin2A = [2tanA]/[1 + tan^2(A)]

    11. cos^2(A) = 1/2[1 + cos(2A)]

    12. sin^2(A) = 1/2[1 - cos(2A)]

    If I typed anything wrong let me know. Good luck deciphering :D


  • Closed Accounts Posts: 884 ✭✭✭ya-ba-da-ba-doo


    Id say the proof for the angles between two lines might appear.. Or else the sin2A = 2tanA/1+tan^2A....


  • Registered Users Posts: 5,533 ✭✭✭Zonda999


    Lads, anyone know where i could find the maths papers from around 94 and 95 online??

    Its just that apparently a few things on paper one came from the 94 paper so i thought they would definitely be worth a look!


  • Closed Accounts Posts: 80 ✭✭yummy91


    aine-maire wrote: »
    Thank GOD the perpendicular distance proof came up last year!


    I know that doesn't help formulate your list,but it does make it a little shorter;)
    The fella on rte 306 said that it was answered terribly last year but, so they might put it on again,, they did stuff like that a few times now I think. It wont hurt to know it lik.


  • Closed Accounts Posts: 49 electriks


    Anyone got tips for honours maths tomorrow for the leaving????:confused::confused::confused:


  • Registered Users Posts: 18,159 ✭✭✭✭phasers


    Study


  • Closed Accounts Posts: 49 electriks


    :confused:


  • Closed Accounts Posts: 5,082 ✭✭✭Pygmalion


    On a more serious note, I'd recommend you brush up on the option you're doing more than any other question, it's the one question you can't avoid or do somethign else instead of.


  • Advertisement
  • Registered Users Posts: 2,365 ✭✭✭spoonbadger


    Pygmalion wrote: »
    On a more serious note, I'd recommend you brush up on the option you're doing more than any other question, it's the one question you can't avoid or do somethign else instead of.
    +1 on this. And to be honest, you have enough time tonight to go over the whole paper before tomorow.

    Pick a hard exam year and do out the paper. Dont bother trying to mark it, just make a note of any questions you had trouble with and do them out of your notes. Best way to study maths, regardless of how much time you have! :).

    Most importantly, asleep before 11:30.

    In terms of what to study in particular...

    Trigonometry and line proofs
    Trig identities
    Maclaurin series
    Integration by parts
    Max/Min questions
    Vectors
    Solving 3d triangles.

    After that, just practice some probability. If you can do all that, it'll at least pull your ass above the pass line.


  • Closed Accounts Posts: 80 ✭✭yummy91


    Dont panic,,,, being positive really does help.
    Know your probability well and your option, go over as many examples of them as you can and go over the proofs.
    I think it helps to go over the things you're worst at in the morning before you go in, like get up about a hour early,, but it depends on what works for you.
    Good luck anyway:)

    AND look in the inspiration thread, :):):).


  • Closed Accounts Posts: 884 ✭✭✭ya-ba-da-ba-doo


    Here how do u get this? Any kind of formula or is it simply just your ability to see the pattern? Hope it doesnt come up tomorrow! HELP PLEASE!


  • Registered Users Posts: 240 ✭✭robz18


    Here how do u get this? Any kind of formula or is it simply just your ability to see the pattern? Hope it doesnt come up tomorrow! HELP PLEASE!
    You need to be able to see the pattern. It's not tough at all. Look at a few questions and answers, you'll get the hang of it in no time.


    Remember that if the signs change the general term will need to be multiplied by a -1 to the power of something.
    The x is usually to the power of 2n plus or minus something too.

    Just remember to always check it for every term (well, not every term obviously, but at least 4 or 5) in the series before you move on to the next question.


  • Closed Accounts Posts: 884 ✭✭✭ya-ba-da-ba-doo


    ^cheers


  • Registered Users Posts: 1,150 ✭✭✭LivingDeadGirl


    FFS my teacher never taught us any of these!!


  • Closed Accounts Posts: 145 ✭✭galway.gaa


    what order are ye doin the questions in? i was thinkin 8 6 7 1 2 3


  • Registered Users Posts: 240 ✭✭robz18


    I'm going to do 2, 8, 4, 5, 3 and then 1.


  • Closed Accounts Posts: 2,026 ✭✭✭Killaqueen!!!


    what are all these tan proofs that people keep talkin about? they're not in my book and can't find it in my notes..don't remember doing that!


  • Advertisement
  • Closed Accounts Posts: 287 ✭✭Des23


    Has the difference equation proof ever come up?
    Could definitely see it happening, people usually take it as a straightforward 20 marks, if they are out to mix things up a bit...


Advertisement