Find the nth term in a Quadratic Sequence

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  • Опубликовано: 27 янв 2025

Комментарии • 174

  • @divangrobler2356
    @divangrobler2356 3 года назад +11

    I've been struggling with this for a full year! Thanks so much this finally makes sense!

  • @krishypo3468
    @krishypo3468 5 лет назад +24

    Thaaaankkk youuu I was definitely going to fail this test thx for this explanation

    • @MathsWithJay
      @MathsWithJay  5 лет назад +2

      @Krishna Pol: Thank you! Hope your test went well!

  • @bluebuddy6191
    @bluebuddy6191 5 лет назад +37

    Thanks I need this for my GCSE

  • @navin7560
    @navin7560 5 лет назад +51

    this helped me impress my maths teacher ty so much

    • @MathsWithJay
      @MathsWithJay  5 лет назад +6

      @navin navin: That's great! Thank you!

  • @yimran5052
    @yimran5052 3 года назад +8

    The explanation was terrific!
    Wonderful Job Frau Jay!

  • @idutal
    @idutal Год назад +2

    This was so confusing to me, you made it so easy to understand, thanks for making this

  • @yxng_shiv
    @yxng_shiv 3 года назад +3

    helped a lot im doing IGCSE extended maths and this really did help, thank you :)

    • @MathsWithJay
      @MathsWithJay  3 года назад +1

      You're very welcome!

    • @poplil3934
      @poplil3934 3 года назад

      @@MathsWithJay Hello, i wanted to ask, why went finding the an, we needed to divide the 16 by 2. pls and thank you.
      Edit: an^2

    • @hirokazuma8979
      @hirokazuma8979 2 года назад

      @@poplil3934 we apparently need to divide by 2 every time

  • @satorujjk
    @satorujjk 2 года назад +1

    4:54 , it doesn't mean you've gone wrong, it just shows that there isn't a bn , so the equation would be an^2+c. I have come across a question where the answer is a quadratic but is in the form of n^2+c instead of n^2+bn+c

    • @MathsWithJay
      @MathsWithJay  2 года назад

      Yes, you're right - that is another possibility

  • @sneak_ios8704
    @sneak_ios8704 3 года назад

    Thank you do much i didnt learned anything at all but dont worry im subscribe and i like you because all your other vedios helped me and you helped makr my teacher proud by me

    • @MathsWithJay
      @MathsWithJay  3 года назад

      Do you have a question about this video?

  • @gkinlen
    @gkinlen 3 года назад

    Best explanation and step by step working of topic Thanks

  • @geraldillo
    @geraldillo 4 года назад +3

    Thank you for sharing your knowledge! Are there similar methods to find higher degree series as well?

  • @anirudhmor2094
    @anirudhmor2094 5 лет назад +2

    awesome your the best math like rananjum

  • @beetlejuice5484
    @beetlejuice5484 6 лет назад +11

    Why is it -8 I am so confused it was positive 8 before

    • @MathsWithJay
      @MathsWithJay  6 лет назад +4

      @Davey: We have found the first part of the formula is 8n^2, so we can subtract that to leave the rest which will be linear. Looking at a simpler example: 3, 8, 15, 24,...The differences go up in 2's, so we know that the formula starts with n^2, so we subtract 1, 4, 9, 16 respectively to leave 2, 4, 6, 8 and can see that the linear formula for these numbers is 2n. So now we can put the two formulas together to get n^2 + 2n

    • @lowlandplum5569
      @lowlandplum5569 3 года назад

      @@MathsWithJay i still dont get how this makes it a minus

  • @itz_fiyin
    @itz_fiyin Год назад

    Thank you, helped me do my homework correctly 🎉

  • @afsanarahman8248
    @afsanarahman8248 4 года назад +1

    Hello I love 💓 you’re explanation Tysm

    • @MathsWithJay
      @MathsWithJay  4 года назад

      @Afsana Rahman: You’re welcome 😊

  • @Saturos_Wifey
    @Saturos_Wifey Год назад

    watching this one night before igcse maths exam cuz none of my teachers helped... thank you for saving my life 🙏

  • @13cicc
    @13cicc 3 года назад

    Best video on the topic!

  • @tanayjyotchawla6259
    @tanayjyotchawla6259 4 года назад +1

    This is the second time I am watching this vid and it is still helpful

    • @MathsWithJay
      @MathsWithJay  4 года назад

      You may like to look at this: ruclips.net/video/5iLAGcz4Vfk/видео.html

  • @elijaha6886
    @elijaha6886 4 года назад +1

    This helped me a lot thanks!!!

  • @babua077
    @babua077 4 года назад +1

    Great vid. Thx for the help.

  • @zobbs
    @zobbs 3 года назад

    Thank you very much Jay

  • @seanhiggins609
    @seanhiggins609 4 года назад +5

    I must be unteachable when you put 8n² in the table and got -32 I was like how

  • @seanzzz3068
    @seanzzz3068 6 лет назад +2

    Good Job thanks for you kind help and tutorial Keep it Up !😉

  • @joeharris8895
    @joeharris8895 5 лет назад +2

    Great vid my brudda

  • @webtree5171
    @webtree5171 3 года назад

    @2:32, why do we divide it by 2??

    • @MathsWithJay
      @MathsWithJay  3 года назад

      Look at the simplest quadratic sequence, the square numbers: 1, 4, 9, 16, 25,... and work out the second differences....what do you get?

  • @richardcao7390
    @richardcao7390 3 года назад +1

    Got a sequence that involves n^3 and took me 4 difference of sum to get same ones... how would I convert the amount of times it takes to get a common difference to the power that I am looking for?

    • @MathsWithJay
      @MathsWithJay  3 года назад

      It should be 3 rows of differences to get n^3

    • @richardcao7390
      @richardcao7390 3 года назад

      Maths with Jay why do u divide it by 6 when it's 3, and divide by 2 when it's 2? what about n^4 ._.

    • @MathsWithJay
      @MathsWithJay  3 года назад

      Maybe you will be able to work out the pattern....just try the simplest sequence of powers of 4: 1, 16, 81, 256, 625, 1296, and what is the 4th difference? Then the pattern should emerge...

  • @Fiercekiller-cs3tq
    @Fiercekiller-cs3tq 4 года назад +1

    Thank you so much ♥️

  • @alicorntube600
    @alicorntube600 2 года назад

    Thank you so much I need this to finish my homework

  • @yasserelbasyouni9751
    @yasserelbasyouni9751 4 года назад +2

    you deserve a LIKE :D

  • @KINGABDUL99
    @KINGABDUL99 3 года назад +1

    Thank u so much.

  • @shawzab_mahmood
    @shawzab_mahmood 4 года назад

    Thanks a lot!!!
    It is really really helping me! God bless you!! 😇😇

  • @someone-tn3dc
    @someone-tn3dc Год назад

    u slayed fr fr

  • @Red_night-e3b
    @Red_night-e3b 8 дней назад

    Is there a easier way to do this ?

    • @MathsWithJay
      @MathsWithJay  8 дней назад

      Let us know if you find a better method

  • @Exotic-zj2di
    @Exotic-zj2di 3 года назад

    Hi, how do i determine which term has the value given to me using the formula?

  • @hari0301
    @hari0301 5 лет назад +1

    what if when you find the an^2 it becomes negative automatically, like -8n^2, Then is it 8n^2?

    • @MathsWithJay
      @MathsWithJay  5 лет назад +1

      @Hari: Why would you change the sign from negative to positive?

    • @LinkNS
      @LinkNS 4 года назад

      i mean if that happened then you would have --8n^2 so it would become positive. but im not 100% sure

    • @sonalhattangadi2486
      @sonalhattangadi2486 3 года назад

      It doesn’t become minus, the sign was there just to signify that it is being subtracted from the other sequence

  • @shafay3262
    @shafay3262 4 года назад

    does it have to be divide by 2 each time? or is that only for this specific quadratic equation?

    • @MathsWithJay
      @MathsWithJay  4 года назад

      You could try it yourself: what happens with the simplest example: 1, 4, 9, 16, 25,...What are the second differences? Then try multiplying up by an integer, say 10, so you get 10, 40, 90, 160, 250,...What are the second differences? Can you answer your question?

    • @shafay3262
      @shafay3262 4 года назад

      @@MathsWithJay Thanks! This video really helped me with my school homework.

  • @saiclique
    @saiclique 4 года назад

    How did it became -3? 5:03

    • @MathsWithJay
      @MathsWithJay  4 года назад

      We need to subtract 3 from -1 to get -4. See ruclips.net/video/vvayGlslby0/видео.html

  • @meowLy_
    @meowLy_ 3 года назад

    aa tysm! greatly appreciated :)

  • @cipherunity
    @cipherunity 6 лет назад +3

    Interesting

  • @ahmedguessad4759
    @ahmedguessad4759 4 года назад +1

    Thank you so mutch

  • @prasunpradip6964
    @prasunpradip6964 4 года назад +1

    tomorrow i have maths exam and this topic was left out ....thanks

  • @Aisha-gd6dq
    @Aisha-gd6dq 3 года назад

    Why do we make it 3n from 8n and how?

  • @poriccrompton
    @poriccrompton 3 года назад

    Right I’ve done this for like 2 hours on the same question pretty sure I’m doing something stupid what’s the nth term for to 1, 3, 6, 10, 15, 21

    • @MathsWithJay
      @MathsWithJay  3 года назад

      This method will work....have you worked out the first stage yet?

  • @randompersonp119
    @randompersonp119 4 года назад

    Do we always have divide by 2 or does it change?🤔

  • @sylviebritz8591
    @sylviebritz8591 3 месяца назад

    Why was 16 divided by 2?

  • @K.DOT11
    @K.DOT11 4 года назад

    What do you do when the differences are not the same? Plz help

    • @MathsWithJay
      @MathsWithJay  4 года назад

      Can you give an example?

    • @K.DOT11
      @K.DOT11 4 года назад

      @@MathsWithJay I think it's known as a cubic sequence

    • @MathsWithJay
      @MathsWithJay  4 года назад

      Do the third set of differences come out to be the same as each other?

    • @K.DOT11
      @K.DOT11 4 года назад

      @@MathsWithJay yes they do

    • @MathsWithJay
      @MathsWithJay  4 года назад

      Then start by dividing the common difference by 6, that will give you the coefficient of the cubed term

  • @lilah5592
    @lilah5592 2 года назад

    Is there a way to find the nth term of a quadratic sequence without using that formula?

    • @MathsWithJay
      @MathsWithJay  2 года назад

      A method that doesn't use a formula?

    • @lilah5592
      @lilah5592 2 года назад

      Like, a way that you can just calculate it without that formula, i learned it that way in high school but i forgot it

  • @trulyross_
    @trulyross_ 4 года назад

    What if you don't have the first 4 but instead the 2nd 3rd and 5th term only

    • @MathsWithJay
      @MathsWithJay  4 года назад

      @Ross: Have you been told what kind of sequence it is? (Linear, quadratic, ...)

    • @trulyross_
      @trulyross_ 4 года назад

      @@MathsWithJayit's quadratic but don't worry i managed to solve it but thanks!

  • @nicholusmalifa2263
    @nicholusmalifa2263 4 года назад

    Why do you do minus 8 instead of positive 8 for 8n^2???

  • @mewa5842
    @mewa5842 5 лет назад +1

    I don’t get where you got + 2 from

  • @koirblx2503
    @koirblx2503 4 года назад +1

    im subbing.

  • @davidthomas4394
    @davidthomas4394 5 лет назад +2

    Why do you divide 16 by 2

    • @MathsWithJay
      @MathsWithJay  5 лет назад +1

      @David: At what time in the video?

    • @davidthomas4394
      @davidthomas4394 5 лет назад +1

      2:36

    • @MathsWithJay
      @MathsWithJay  5 лет назад +1

      @David: Think about the sequence of square numbers: 1, 4, 9, 16, 25,... The differences are 3, 5, 7, 9,... And the differences between the differences are 2...so we divide by 2 to get the number to multiply n^2

    • @davidthomas4394
      @davidthomas4394 5 лет назад +2

      @@MathsWithJay Oh thanks

  • @nadirsajid448
    @nadirsajid448 4 года назад

    What if the difference you get (when finding bn+c),is different ?

    • @MathsWithJay
      @MathsWithJay  4 года назад

      @Nadir Sajid: What is your sequence?

  • @Yhman
    @Yhman 5 лет назад +1

    What if 8n squared is negative

    • @MathsWithJay
      @MathsWithJay  5 лет назад +2

      @Henry: Squaring would always give a positive number.

    • @Yhman
      @Yhman 5 лет назад +3

      @@MathsWithJay thanks really helpful

  • @hello5810
    @hello5810 9 месяцев назад

    thank you !

  • @hari0301
    @hari0301 5 лет назад +1

    what if the diffrence of the diffrence is 0

    • @MathsWithJay
      @MathsWithJay  5 лет назад +1

      @Hari 0: Which difference? The first or second?

  • @EvenOdd-v1d
    @EvenOdd-v1d 2 месяца назад

    helpful thanks

  • @chandrababuhansda54
    @chandrababuhansda54 4 года назад

    I can't understand at the end that is( +2) concept .plss mam reply me

    • @MathsWithJay
      @MathsWithJay  4 года назад

      At what time in the video?

    • @chandrababuhansda54
      @chandrababuhansda54 4 года назад

      @@MathsWithJay at 5:36, i mean c=2 is come from where

    • @MathsWithJay
      @MathsWithJay  4 года назад +1

      -1+3=2 See ruclips.net/video/vvayGlslby0/видео.html

  • @AP-vy9bc
    @AP-vy9bc 4 года назад

    I got -2 and +3 would that also be right?

  • @geronimalagunda7252
    @geronimalagunda7252 5 лет назад +1

    what if the difference is 2

    • @MathsWithJay
      @MathsWithJay  5 лет назад +1

      @Geronima: We always divide the difference by 2. So 2/2 = 1.

  • @TheRealBleach
    @TheRealBleach 5 лет назад +1

    Thanks

  • @amaniceh
    @amaniceh 3 года назад

    why n=4?

    • @MathsWithJay
      @MathsWithJay  3 года назад

      At what time in the video?

    • @amaniceh
      @amaniceh 3 года назад

      @@MathsWithJay 5:50, i mean, why do we choose 4 of all numbers?

  • @thenormalkid3781
    @thenormalkid3781 3 года назад

    ty bro

  • @joshreyes6158
    @joshreyes6158 4 года назад

    Why is it plus 2

    • @MathsWithJay
      @MathsWithJay  4 года назад

      At what time in the video?

    • @joshreyes6158
      @joshreyes6158 4 года назад

      5:30

    • @MathsWithJay
      @MathsWithJay  4 года назад

      That part is looking at a linear sequence like: ruclips.net/video/vvayGlslby0/видео.html

  • @kjono4611
    @kjono4611 4 года назад

    If you had to find the differences 4 times before they converge, would that mean the answer should be in the form an^4 + bn^3 + cn^2 + dn + e or should it just be an^2 + bn + c?
    The sequence is 1, 3 ,12, 39, 120, 316, ...
    which makes the differences 2, 9, 27, 81, 196
    and then 7, 18, 54, 115
    then 11, 36, 61
    then 25, 25
    If it should be the first option, do I just repeat the steps again and again or is there another way to do this?

    • @MathsWithJay
      @MathsWithJay  4 года назад

      Kieran, it's the first option. You could find the coefficient of n^4 first and so on.

  • @bobbydong1228
    @bobbydong1228 3 года назад

    Pls can you help me out with 2,12,36,80.

    • @MathsWithJay
      @MathsWithJay  3 года назад

      That's harder than this one....it will involve cubing, not just squaring. If you haven't looked at cubic nth term yet, try writing each number in your pattern as a product of two numbers and look at 2 patterns...

  • @dimaalhamoud
    @dimaalhamoud Год назад

  • @sirlordhobo1061
    @sirlordhobo1061 4 года назад

    tysm

  • @ismaeelrafiq8028
    @ismaeelrafiq8028 4 года назад

    My exam is tomorrow 😭

  • @t7yphaon16
    @t7yphaon16 6 лет назад +1

    im vegan btw, very cool!