Squirt Posted September 12, 2011 Report Share Posted September 12, 2011 Hi I've done some study last week or so for my maths mocks tomorrow. I have a question about graphing If you have a table Eg X Y 1 5 2 14 3 27 4 44 And you have to find an equation for this I know you get ax^2 + bx Ie Difference of 14-5=9 27-14=13 44-27=17 and difference of all of them is 4 So there is two jumps giving you x^2 but how do you get the whole equation? Is it just trial and error? Quote Link to comment Share on other sites More sharing options...
Squirt Posted September 12, 2011 Author Report Share Posted September 12, 2011 Guess it is algebra? Quote Link to comment Share on other sites More sharing options...
Zev Posted September 12, 2011 Report Share Posted September 12, 2011 Math - Nooooooooo..... :nilly: Quote Link to comment Share on other sites More sharing options...
Squirt Posted September 12, 2011 Author Report Share Posted September 12, 2011 :-? Afraid so Quote Link to comment Share on other sites More sharing options...
Adrienne Posted September 12, 2011 Report Share Posted September 12, 2011 are you allowed to use a graphing calculator? Quote Link to comment Share on other sites More sharing options...
Squirt Posted September 12, 2011 Author Report Share Posted September 12, 2011 Yeah, I have one but I'm not sure how to plot co ordinates to find an equation or put them in a table and find an equation, it's a casio fx 9750ga plus if that helps? Quote Link to comment Share on other sites More sharing options...
antwan Posted September 12, 2011 Report Share Posted September 12, 2011 y=2x^2+3x Quote Link to comment Share on other sites More sharing options...
Squirt Posted September 12, 2011 Author Report Share Posted September 12, 2011 Yeah, I managed to get to that but I don't know how Quote Link to comment Share on other sites More sharing options...
antwan Posted September 12, 2011 Report Share Posted September 12, 2011 It's been ages since I've done this. I just cheated and used excel Quote Link to comment Share on other sites More sharing options...
Squirt Posted September 12, 2011 Author Report Share Posted September 12, 2011 Quote Link to comment Share on other sites More sharing options...
Adrienne Posted September 12, 2011 Report Share Posted September 12, 2011 is that the green calculator? Quote Link to comment Share on other sites More sharing options...
Squirt Posted September 12, 2011 Author Report Share Posted September 12, 2011 No it's dark blue and white but it could be similar? Quote Link to comment Share on other sites More sharing options...
phoenix44 Posted September 12, 2011 Report Share Posted September 12, 2011 It's the same as the green and white one, but the colour screen version. Quote Link to comment Share on other sites More sharing options...
Squirt Posted September 12, 2011 Author Report Share Posted September 12, 2011 It's got a black and white screen, with on the menu, Run Stat Mat List Graph Dyna Table Recur Conics Equa Prgm Tvm Link Content Mem Quote Link to comment Share on other sites More sharing options...
Adrienne Posted September 12, 2011 Report Share Posted September 12, 2011 my daughter has the same calculator and she got y=0x^2+1x-5 try going from main menu into STAT and then putting in x into list 1 (1,2,3,4) and then y into list 2 (5,14,27,44) and then pressing F2 which is CALC and then pressing F3 which is REG and then F3 which is X^2 and it will give you what a,b,c are for y=ax^2+bx+c see how you go with this. Thats how she would do it. She is not sure if it is right though. Quote Link to comment Share on other sites More sharing options...
Squirt Posted September 12, 2011 Author Report Share Posted September 12, 2011 Agh got it thank you so much I got 2x^2+3x+0 though? And thanks to everybody else that contributed :thup: Quote Link to comment Share on other sites More sharing options...
supasi Posted September 12, 2011 Report Share Posted September 12, 2011 :nilly: :nilly: :dunno: Quote Link to comment Share on other sites More sharing options...
calculator Posted September 12, 2011 Report Share Posted September 12, 2011 Whoo, I do like how now every one is doing simple questions in your the calculator now, I always had to do them in my head, and that was only a couple of years ago, what is the mathematics world coming to. Quote Link to comment Share on other sites More sharing options...
Squirt Posted September 12, 2011 Author Report Share Posted September 12, 2011 Yeah I could do it in my head but it'd take longer than what it would on the calc. I'm pretty average at maths and have gone straight excellences this year :thup: Quote Link to comment Share on other sites More sharing options...
calculator Posted September 12, 2011 Report Share Posted September 12, 2011 Yeah I could do it in my head but it'd take longer than what it would on the calc. I'm pretty average at maths and have gone straight excellences this year :thup: That is good, although with maths you should always be aiming for excellence, as any thing less is disappointing. You should always do as many questions as you can in your head and not with the calculator, it helps your understanding of how maths works, and makes the harder maths later on easier to understand. Sorry for the rant, its just maths is cool, dont let any one tell you it isnt Quote Link to comment Share on other sites More sharing options...
Adrienne Posted September 12, 2011 Report Share Posted September 12, 2011 If you can use a calculator in exams and know what you are doing then its silly not to. You have to know the process to get the correct result anyway. My daughters Y13 and the only maths she is doing this year is Stats and Modelling. Quote Link to comment Share on other sites More sharing options...
Squirt Posted November 13, 2011 Author Report Share Posted November 13, 2011 :bounce: anyone good at stats? I was reading through some sample papers today, and noticed a comment by the marker. Is it ok to have two different sample sizes? Say one is 50 people and the other is 54, could this affect the data? It said "many candidates were under the illusion that because there was more than one group than another, the statistics were invalid in some way; a valid teaching point". I realize it's too late to ask my Maths teacher, so can anyone help out? I can tell that they are going to do it tomorrow, because in the past like 3 years they've done it. :digH: Quote Link to comment Share on other sites More sharing options...
phoenix44 Posted November 13, 2011 Report Share Posted November 13, 2011 4 more people shouldn't negatively or positively affect the data. Totally generic and non specific statement though. Quote Link to comment Share on other sites More sharing options...
Squirt Posted November 13, 2011 Author Report Share Posted November 13, 2011 Thanks P44 Oh and another quick one Difference between sample space and sample size? I think size is how many there are, but what is space? Got it, sample space is all the outcomes of eg rolling a dice Sample size is the number of people you interview, or how many tests you do ect? So the question is normally Analyze the data accuracy, including the data collection methods. I might stick in there, even though the two sample space(size?) are different this shouldn't affect the data accuracy, due to it being a small figure. Quote Link to comment Share on other sites More sharing options...
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