kyska Posted December 8, 2008 Report Share Posted December 8, 2008 Alright, I guess I'll just keep graphing and hope I hit something...even though we have never done Vieta's formula in class...BTW, is the final conjecture completely different from what we had earlier? i.e, nothing to do with slopes and the a value then?Ah well, lemme see if there is a pattern in there...though I don't know how to interpret it...Thanks.I have done this portfolio, if u need more help PM Reply Link to post Share on other sites More sharing options...
takat Posted December 9, 2008 Report Share Posted December 9, 2008 I have done this portfolio, if u need more help PMHelp would be much appreciated... Reply Link to post Share on other sites More sharing options...
Kaciukas Posted December 14, 2008 Report Share Posted December 14, 2008 Have the same problem with the investigation questions 5-6. can anyone help me ? Reply Link to post Share on other sites More sharing options...
BIBO92 Posted December 20, 2008 Report Share Posted December 20, 2008 Hey, i am stuck on number 5 and 6. I am getting D=0 but everyone is saying that we have to use Vieta's formula. I never took it and when I researched it on the net i didnt see how this can solve for D and the conjecture for cubics.Can somebody please help me Reply Link to post Share on other sites More sharing options...
prmjl Posted January 25, 2009 Report Share Posted January 25, 2009 i seriously need help on Q5 please anyone? Reply Link to post Share on other sites More sharing options...
Intelligent-Bullshitter Posted January 27, 2009 Report Share Posted January 27, 2009 I have done this portfolio, if u need more help PMokay, i really need your help, and thanx Reply Link to post Share on other sites More sharing options...
Intelligent-Bullshitter Posted January 27, 2009 Report Share Posted January 27, 2009 Oh God this brings back some memories lol I had to do 60 pages on this, about 20 pages or so had a huge graph on each of them because of No. 2. And I've found two conjectures for Q.5 and 6 - one was that D always equal to zero, and the other one was a little different.I could give you a hint but I'm not sure if I'm allowed to here......so yup, if you need some help I could help you - just PM me.hi how would i pm you, i am a newbie, lllol, and i need help Reply Link to post Share on other sites More sharing options...
Intelligent-Bullshitter Posted January 27, 2009 Report Share Posted January 27, 2009 I have finish this ia already. to give you guys some hintfor part five, the conjecture would be SL = x2 ‐x1‐ S1 = x4 –x3‐ SR = x6 –x5D = | SL ‐ S1 ‐ SR |=0for part 6 use sum of root to prove your conjecture, if you have any? pm mehopes that helpsthankshi for part six what conjecture are you talking about? Reply Link to post Share on other sites More sharing options...
Ongfufu Posted February 3, 2009 Report Share Posted February 3, 2009 Try using Vieta's (or Viete's) Formula for #5 and 6. Reply Link to post Share on other sites More sharing options...
Munesh Yagna Posted February 7, 2009 Report Share Posted February 7, 2009 oh please....can someone explain me this viett's theorem... Reply Link to post Share on other sites More sharing options...
zolek78 Posted February 9, 2009 Report Share Posted February 9, 2009 i'm working on this portfolio at the moment. I think i've got the right conjecture up to Q4. Well, Q5 and 6 cause some problem because i can't find the roots on general cubic formula. I tried to find the Vieta's formula, i used it although i'm not very sure how to use. Can someone give me any hint to use Vieta's theorem? Do we have to perform any substitution or swap the formula around?Also, for Q6, how do you prove the conjecture? I dont know how to find x for general polynomial formula. Do we still use Vieta's theorem? (i'm stuck because on the website, i only found the theorem applied to degree 3)Anyway, it's frustrated to see ppl writing 60 pages of work for this one. T.T Reply Link to post Share on other sites More sharing options...
Hughie Posted February 10, 2009 Report Share Posted February 10, 2009 I only wrote 60 pages because I did huge graphs lol and I tried out a lot of graphs for Q2, so Q1 and Q2 combined together accounted for about 30 pages I think.I never used Vieta's formula......wonder what it is O_o Reply Link to post Share on other sites More sharing options...
Ongfufu Posted February 14, 2009 Report Share Posted February 14, 2009 http://mathworld.wolfram.com/VietasFormulas.html, this is a good site that explains Vieta's formula. For cubic polynomial, arrange the general formula to be like line 14 and 15 on the website. Since r1, r2, r3 are the roots of the cubic, line 15 shows that the sum of the roots is the coefficient of the x squared term. When the cubic is intersected with another linear line, equate the right side of the equation (line 14) and the general formula for a linear line (mx+b). Then rearrange the equation to let 0 be on right side and you'll see that the coefficient of the x squared term has not changed.If anyone has any questions, PM me. Reply Link to post Share on other sites More sharing options...
Shreeyash Saboo Posted February 26, 2009 Report Share Posted February 26, 2009 (edited) No helping people!, let them do it themselves.-AbooAhhhh, ok... Can you please help me with question 2 ? It says various values of 'a'; does that mean we can also change values of b? Edited February 26, 2009 by Shreeyash Saboo Reply Link to post Share on other sites More sharing options...
Ongfufu Posted March 1, 2009 Report Share Posted March 1, 2009 Can you please help me with question 2 ? It says various values of 'a'; does that mean we can also change values of b?You could always change the value of b, even in question 1. There's no limit on value of b. Reply Link to post Share on other sites More sharing options...
LinuxBeta Posted March 1, 2009 Report Share Posted March 1, 2009 When doing this portfolio, while the first thing that comes to mind is Vieta's formula, you cannot use it in this case. I forget the specific reasons...I did this portfolio about a month ago. What I found was that all you really need for part 6 is a lot of examples. If you just work on the examples, you will definitely see a common pattern emerging. All you have to do after that is to arrange them into a neat conjecture. Don't over-complicate things unnecessarily. Reply Link to post Share on other sites More sharing options...
ibhatesme Posted March 1, 2009 Report Share Posted March 1, 2009 i still don't understand 5 though. Is D=0? people are saying that but i'm actually getting a D value. but i can't seem to coorelate it to an equation. Help? Reply Link to post Share on other sites More sharing options...
ibhatesme Posted March 1, 2009 Report Share Posted March 1, 2009 http://mathworld.wolfram.com/VietasFormulas.html, this is a good site that explains Vieta's formula. For cubic polynomial, arrange the general formula to be like line 14 and 15 on the website. Since r1, r2, r3 are the roots of the cubic, line 15 shows that the sum of the roots is the coefficient of the x squared term. When the cubic is intersected with another linear line, equate the right side of the equation (line 14) and the general formula for a linear line (mx+b). Then rearrange the equation to let 0 be on right side and you'll see that the coefficient of the x squared term has not changed.If anyone has any questions, PM me.well if the x squared term doesn't change, then are you saying that it has something to do with that term? if so, i still can't find a coorelation between the x squared term and the D value. I kept the numerator to 1 since it's just y=x and y=2x but, idk how to do this. Reply Link to post Share on other sites More sharing options...
LinuxBeta Posted March 2, 2009 Report Share Posted March 2, 2009 You have to use a little bit of creativity here. You are no longer given the EXACT formula for D. However, I will give you that: SL = x2-x1SM = x4-x3SR = x6-x5Using these, subtract two of them from one of them...and you should get zero. Play around with the values, and you'll get it. For this portfolio, I found that the best way to find things out is using many examples and then trying to find out the common pattern. Reply Link to post Share on other sites More sharing options...
Shreeyash Saboo Posted March 3, 2009 Report Share Posted March 3, 2009 Approximately how many diagrams should be put in for every question considering the assesment criteria Reply Link to post Share on other sites More sharing options...
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