How to find a formula for a quadratic sequence (3 examples)

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  • เผยแพร่เมื่อ 24 พ.ย. 2024

ความคิดเห็น • 20

  • @yoav613
    @yoav613 3 ปีที่แล้ว +16

    Nice way. I always solved it like i learned in school a2-a1=b1 a3-a2=b2..an-a(n-1)=b(n-1) so summing all we get an=a1 +(b1+b2..+b(n-1)) which is the sum ofn-1 arithemetic series.

    • @1224chrisng
      @1224chrisng 3 ปีที่แล้ว

      I guess that's like the discrete version of an integral, that's interesting

  • @emanuelvendramini2045
    @emanuelvendramini2045 3 ปีที่แล้ว +6

    Very nice video and I've loved the trick with A! I think that you could use one more trick for the first difference in order to get B, 'cuz the formula for the first difference would be A(2n+1) + B. Taking the last example, once we know that A = 6, taking the first term of the first difference we get 18 = 6(2*(1) + 1) + B = 18 + B, and then B = 0. Finally, C can be obtained with the first term of the sequence, using that A(1)² + B(1) + C = 1, we have 6 + 0 + C = 1 and therefore C = -5.

  • @JacobBombastic-qb6hh
    @JacobBombastic-qb6hh 19 วันที่ผ่านมา +1

    Thank you very much method 2 helped me tons

  • @vioplam
    @vioplam หลายเดือนก่อน

    Thank you I learned this in Highschool but in college they tried teaching it through guess and check. Had to find this method again

  • @D_folder
    @D_folder ปีที่แล้ว

    Finally someone who does it properly😢

  • @danpost5651
    @danpost5651 3 ปีที่แล้ว +3

    You can create a new series by subtracting An^2 from the original series (you only need the first two values in this new series). Then the first difference will be equal to B. Then, subtracting A1 and B1 from the first value in the first sequence gives you C

  • @Yaraisme13
    @Yaraisme13 ปีที่แล้ว

    Thank you so much for this!
    I have a math hw which is due tomorrow and i didnt understand the lesson that much, but thank you again for your help !

  • @mathsandsciencechannel
    @mathsandsciencechannel 3 ปีที่แล้ว +1

    Great video

  • @kxraxh
    @kxraxh ปีที่แล้ว +2

    wala na 'kong magets. kaso pag bumagsak hindi ako makakapagtapos, pag 'di ako nakapagtapos hindi ako magkakatrabaho, pag wala akong trabaho magkakasakit ako, kapag nagkasakit ako mamatay ako kasi nga wala akong pambili ng gamot kasi wala akong trabaho. kaya shet panoodin ko ulit 2hs loop (nahihilo, nalilito)

    • @osetra8803
      @osetra8803 2 หลายเดือนก่อน

      legit

  • @theratingguy5659
    @theratingguy5659 ปีที่แล้ว

    nice video thanks

  • @pingudash2420
    @pingudash2420 3 ปีที่แล้ว +1

    hi sir this is very cool

  • @petereziagor4604
    @petereziagor4604 3 ปีที่แล้ว

    Nice and easy 👍
    Thank you

  • @jamesstrickland833
    @jamesstrickland833 3 ปีที่แล้ว +1

    (2nd level diff)/2*(n-1)(n-2)+(1st level diff)(n-1)+a1 ... boom

  • @dimi1357
    @dimi1357 3 ปีที่แล้ว +2

    A shortcut you can use is to generate a_0 (because you can calculate the difference between a_0 and a_1), and then you get C for free because: a_0=A*0^2+B*0+C=C.

  • @pencil6711
    @pencil6711 ปีที่แล้ว

    lmao the pokeball

  • @broytingaravsol
    @broytingaravsol 3 ปีที่แล้ว +1

    新開的頻道?

  • @shickeny
    @shickeny 2 หลายเดือนก่อน

    im so confused

  • @Owenwtf
    @Owenwtf ปีที่แล้ว +1

    WRONG THIS GUY IS LYING, IT DOESN"T WORK