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    (Original post by physicsmaths)
    quoting shud be ok tbh. it is one line prof anyway just say "let A=arctan n B= leads to A+B=...



    (Original post by Zacken)
    I'd add in the extra line of proof. It shouldn't take longer than 10 seconds extra than just quoting it.
    Okay thanks, I'll just prove it since it's not too big a deal
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    (Original post by fa991)
    Okay thanks, I'll just prove it since it's not too big a deal
    This is the way I would do it:
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    (Original post by physicsmaths)
    think about |x|=x or -x dependng if x>=0 or x<0.
    Sorry, I'm a bit confused. I thought it may be because the limits are greater than or equal to 0, so the mod signs are not needed. Is that right?


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    (Original post by Zacken)
    This is the way I would do it:
    Ah thanks a lot, that's literally a one liner.
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    (Original post by Zacken)
    This is the way I would do it:
    At the STEP Easter School I was actually called out by an offer-holder that this proof is not 'valid' while doing that STEP II question that starts with proving it. Makes me suspicious that my math is wrong everytime I do this one-liner, lol.


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    (Original post by Insight314)
    At the STEP Easter School I was actually called out by an offer-holder that this proof is not 'valid' while doing that STEP II question that starts with proving it. Makes me suspicious that my math is wrong everytime I do this one-liner, lol.


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    I don't see why it's not valid. Tangent is injective in any interval of width pi/?
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    (Original post by Insight314)
    At the STEP Easter School I was actually called out by an offer-holder that this proof is not 'valid' while doing that STEP II question that starts with proving it. Makes me suspicious that my math is wrong everytime I do this one-liner, lol.


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    he is probs talking about not paying attention to ranges and stuff like that which Is needed i think since were messing with inverse functions(these inverse functions can be *******s sometimes.
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    thinking about rangesn stuff.
    prove that for a,b>0 and ab>1 that
    arctanA+arctanB=pi+arctan(a+b/1-ab)
    Find the corresponding result when a,b<0
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    (Original post by Zacken)
    I don't see why it's not valid. Tangent is injective in any interval of width pi/?
    When did I say it was not valid? The guy thought it wasn't valid for some reason. Just like physicsmaths pointed out, he was probably confused with range/domain of the function but I think he mostly got caught out for thinking that I was adding tan expressions i.e tan X + tan y = tan (X+y) since he literally told me that lol.


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    (Original post by Insight314)
    When did I say it was not valid? The guy thought it wasn't valid for some reason. Just like physicsmaths pointed out, he was probably confused with range/domain of the function but I think he mostly got caught out for thinking that I was adding tan expressions i.e tan X + tan y = tan (X+y) since he literally told me that lol.


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    He is right to be concerned since that doesn't hold for all x,y.
    npi stuff etc.
    Zacken is agrreing with you saying he can't see why it isn't valid for that II question.


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    (Original post by physicsmaths)
    He is right to be concerned since that doesn't hold for all x,y.
    npi stuff etc.
    Zacken is agrreing with you saying he can't see why it isn't valid for that II question.


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    Yep I knew that it was a bit more technical too which is why I was confused when all you guys were saying that it was a one-liner but every time I did the proof it always took me a while to sort out the technical stuff.

    Because with \arctan a+\arctan b=\arctan\left(\dfrac{a+b}{1-ab}\right) the tangents of each side are equal but that only shows that the two sides differ by an integer multiple of \pi. You then have to consider the relevant ranges of the two sides. But most of the time it's quite easy in STEP since usually you know something about the ranges of the two sides.
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    Are there any hard or obscure bits of FP2 that I should learn before tomorrow?
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    Don't you just love it when you do last years paper the day before your real exam and get a B... **** MY LIFE
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    More of a general question. I find when I get into the zone of doing step questions i usually do well (i.e get a 1 or S on mocks) but it usually takes me a few days to get into the proper mind set (maybe 3 or 4).

    The problem I have is that i have 13 other exams to sit over the next 2.5 weeks so i won't be able to devote any time to getting into the proper mindset for step. For Step 1 i wont be able to do any prep but it's step 1 so who cares? For step 2 i'll have a day to prepare which helps and on step 3 i have about 4 hours to prepare which will be a serious challenge for me.

    How would you recommend I get in the proper mindset in such a short period of time? It's quite annoying because once I stop doing step, within a day or 2 I start struggling with even some step 1 q's and generally take longer to do questions.
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    (Original post by KingRS)
    More of a general question. I find when I get into the zone of doing step questions i usually do well (i.e get a 1 or S on mocks) but it usually takes me a few days to get into the proper mind set (maybe 3 or 4).

    The problem I have is that i have 13 other exams to sit over the next 2.5 weeks so i won't be able to devote any time to getting into the proper mindset for step. For Step 1 i wont be able to do any prep but it's step 1 so who cares? For step 2 i'll have a day to prepare which helps and on step 3 i have about 4 hours to prepare which will be a serious challenge for me.

    How would you recommend I get in the proper mindset in such a short period of time? It's quite annoying because once I stop doing step, within a day or 2 I start struggling with even some step 1 q's and generally take longer to do questions.
    Oh poor you, with 13 exams.

    Grind questions the day before your STEP exams. There are people with way more exams than you out there, there is no need to complain. If you do one question every half an hour for 4 hours you would easily be able to get into the mindset since that equates to one mock and more worth of questions. Also, I don't understand what you mean by getting into the mindset, problem-solving abilities are not some kind of temporary magic that go away after a few days. If you can get an S right now, you will most likely get an S in the exam unless you panic like physicsmaths did. Relax.


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    Just finished I 2015, who's up for peer marking?


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    (Original post by Insight314)
    Oh poor you, with 13 exams.

    Grind questions the day before your STEP exams. There are people with way more exams than you out there, there is no need to complain. If you do one question every half an hour for 4 hours you would easily be able to get into the mindset since that equates to one mock and more worth of questions. Also, I don't understand what you mean by getting into the mindset, problem-solving abilities are not some kind of temporary magic that go away after a few days. If you can get an S right now, you will most likely get an S in the exam unless you panic like physicsmaths did. Relax.
    ******** all over his problems isn't going to help him relax, lol
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    Hey everyone.

    I'm preparing for STEP, and I didn't previously know that this thread existed. Now nobody laugh, but I don't actually know the detailed specification beyond the fairly vague one given by Cambridge Assessment. I looked in the formula booklet and there is a load of stuff in there that I haven't actually studied (having only done up to S2 at school) including estimators, and the t distribution

    Should I begin to panic, or is there material in the booklet that you don't need?

    EDIT: I should add that I finished school in 2014, and am applying to university as a mature student for courses starting in 2017, and am taking step 1, 2 and 3
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    (Original post by jjsnyder)
    Just finished I 2015, who's up for peer marking?


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    Im just finishing my lunch then I have 1 hour left on it. Are u up for exchanging a couple qs then?
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    (Original post by welcomemat96)
    Hey everyone.

    I'm preparing for STEP, and I didn't previously know that this thread existed. Now nobody laugh, but I don't actually know the detailed specification beyond the fairly vague one given by Cambridge Assessment. I looked in the formula booklet and there is a load of stuff in there that I haven't actually studied (having only done up to S2 at school) including estimators, and the t distribution

    Should I begin to panic, or is there material in the booklet that you don't need?

    EDIT: I should add that I finished school in 2014, and am applying to university as a mature student for courses starting in 2017, and am taking step 1, 2 and 3
    I've never used about 3/4 of the booklet before, don't worry.
 
 
 
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