Explicit and recursive definitions of sequences | Precalculus | Khan Academy

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  • Опубликовано: 28 янв 2025

Комментарии • 314

  • @Jaguar404x
    @Jaguar404x 8 лет назад +210

    I just spent two days in class trying to learn recursive sequences and I didn't understand it but somehow this guy on the internet taught me it in less than 10 minutes. HOW. IS. HE. THIS. GOOD. AT. TEACHING.

    • @shayaan7584
      @shayaan7584 6 лет назад +2

      HE. USES. BLACK. MAGICCCCCCCC!!!!!

    • @shayaan7584
      @shayaan7584 6 лет назад

      JK

    • @tannerq8900
      @tannerq8900 6 лет назад +10

      Cause now your paying attention.

    • @Cgg222
      @Cgg222 2 года назад +2

      He is Saul Goodman

    • @-clipz-
      @-clipz- Год назад

      Prayers turn to God may everyone everywhere be blessed and healed and protected in Jesus name amen

  • @bobchlarson788
    @bobchlarson788 7 лет назад +837

    Shoutout to all the other people failing math who came here to try to get help and got more confused

    • @cubeheads4everxtreme638
      @cubeheads4everxtreme638 7 лет назад +31

      same and thanks for the shoutout

    • @at-xh1yv
      @at-xh1yv 7 лет назад +42

      i came here since my teacher is too lazy to teach & tells us to come here :-)

    • @dontplay2912
      @dontplay2912 6 лет назад +15

      Bob Chlarson I’m not failing xd😂. Just needed clarification bc I’m taking algebra in 7th grade.

    • @bethegreatest4976
      @bethegreatest4976 5 лет назад +3

      SOCCER IS LIFE

    • @ethanisnothere1375
      @ethanisnothere1375 4 года назад +1

      Lol that means me

  • @chocolatetwixbarnow4983
    @chocolatetwixbarnow4983 8 лет назад +416

    Wait, this is precalculus? I'm learning this in Algebra I. Wtf.

    • @salmah725
      @salmah725 6 лет назад +24

      Chocolate & Twix Bar Now precalc is the same as algb 1 Lmfaoo

    • @marlyl1957
      @marlyl1957 6 лет назад +19

      you mustve been in an honors class lol

    • @olamidefagbewesa870
      @olamidefagbewesa870 6 лет назад +5

      Same

    • @quintonreese5880
      @quintonreese5880 6 лет назад +12

      SAME i have this is algebra 1 honors btw im a freshman

    • @ramelango3882
      @ramelango3882 6 лет назад +22

      I take this for algebra 1 too lol
      I’m in an honors class as well
      I’m in 8th grade

  • @yougotnoyams7325
    @yougotnoyams7325 7 лет назад +702

    And then satan said: " put the alphabet in math!"

  • @THESOGGYSPONGE
    @THESOGGYSPONGE 10 лет назад +81

    My brain just imploded

  • @TheBancho22
    @TheBancho22 12 лет назад +22

    "You can find every other term in terms of the term before it." :D nice

  • @user-sx1up5oh2d
    @user-sx1up5oh2d 6 лет назад +25

    Thank you this really helps, I am currently taking a math class right now and the teacher doesn’t even take notes and he is very uncommunicative, so it is hard to figure out how to do the math, but everyone else in the class gets it

  • @ranic993
    @ranic993 9 лет назад +228

    I am now more confused

  • @elliptix9344
    @elliptix9344 6 лет назад +4

    OMG now I understand THANK YOU SO MUCH I emailed my teacher so THANK YOU I DON'T NEED HER HELP ANYMORE :)))))

  • @mavericklucas594
    @mavericklucas594 4 года назад +12

    Thanks, I was struggling to understand this on my homework and this helped a lot.

  • @sonofjesus1464
    @sonofjesus1464 9 лет назад +16

    I found how to do this. Lol God bless :D

  • @RIMPND
    @RIMPND 8 лет назад +257

    5:28 The most racist quote on khan academy...

  • @noperope325
    @noperope325 4 дня назад

    Khan videos help 80% of the time and this was one of the 20

  • @joylox
    @joylox 7 лет назад +6

    You need to do a video on solving these, and/or a discrete math series! It gets a bit confusing to solve. My last assignment was proving the Fibonacci sequence, which is cool, but a little challenging.

  • @FallingDrop234
    @FallingDrop234 5 месяцев назад +1

    I swear to god I’m just gonna get a bunch of math books one summer and study up to precalc so I never have to deal with this again

  • @ditrixgenesis781
    @ditrixgenesis781 6 лет назад +3

    I'm here for my Math 232 class, but that last little statement applies to more than just math (for myself, Comp Sci 250).
    Explicit code is very direct, but will take forever (hyperbolically) if the correct problem comes up, so the solution is to use a recursive code with a beginning term.
    Cool

  • @charmingcurls7401
    @charmingcurls7401 Год назад +1

    Thank you so much!
    Helped me so much!!

  • @gabrielgazeti5883
    @gabrielgazeti5883 7 лет назад +50

    2+2 is 4 -1 thats 3 quick maths

  • @tannerq8900
    @tannerq8900 6 лет назад +5

    Thanks, my teach went over this in 20 minutes, that may seem like a good amount of time, but do that, with only 3 problems, and him not fully explaining how it is done, or what explicit, and recursive equations are!
    (Don't get me wrong he's a great math teacher, but he needs to explain a few things more. Instead if hinting at what something is.)

  • @ashleyb7887
    @ashleyb7887 4 года назад +1

    this man saves my life every time

  • @jessicaledwick899
    @jessicaledwick899 Год назад

    Thank you! It was quite a search to find a youtube video that tells the difference between recursive and explicit.

  • @theblackk-night3334
    @theblackk-night3334 8 лет назад +6

    I started my test yesterday and I'm now watching this before school the next day so I can pass it

  • @specter1001
    @specter1001 6 лет назад +2

    This is a supremely helpful video. thank you!

  • @at-xh1yv
    @at-xh1yv 7 лет назад +87

    i came here since my teacher is too lazy to teach & tells us to come here :-)
    no one? ok

    • @derrickseo503
      @derrickseo503 7 лет назад +1

      hello lol

    • @lovi9258
      @lovi9258 6 лет назад +1

      samee

    • @SequinBrain
      @SequinBrain 4 года назад +2

      This increasingly disgusting, bad habit teachers have wasn't a thing in the 70s or 80s, since the iNet was in its infant stages. I'm trying to get more oversight on bad teachers and how to remove them, but evidently, this process is also in its infant stages or doesn't exist at all.

  • @aesthetic_animes9331
    @aesthetic_animes9331 3 года назад +1

    Thank you so much! This really helped! The way we do it we substituted k to n so it kinda confused me a little but now I got it!

  • @rachelpark3295
    @rachelpark3295 11 лет назад +1

    You make this so easy
    Thank you!

  • @victort.4798
    @victort.4798 3 года назад +5

    POV: it’s 5am on a Sunday during covid virtual school and you’re cramming for a cumulative precalc exam due at the end of the day :)

    • @mastergamer4928
      @mastergamer4928 3 года назад

      Precalc exam? I'm doing this in algebra 1

  • @Seth-pf4bo
    @Seth-pf4bo 6 лет назад +1

    I thank you for getting me through middle school

  • @trippinthecreator3148
    @trippinthecreator3148 7 лет назад +4

    I don't know if it will help anyone, but learned it as F(n) and not A(k). Should't make a difference, but it's a bit confusing at first.

    • @xiomara8610
      @xiomara8610 4 года назад

      Thank you, i was genuinely very confused on where A(k) came in my homework.

    • @parkjena1923
      @parkjena1923 3 года назад

      thank you! you just answered what i was looking for :D

  • @ericawu8779
    @ericawu8779 4 года назад +4

    "This is not an attractive color"
    lmao 😂

  • @iamnottweezy
    @iamnottweezy 6 лет назад +1

    i got a 47% on my test so now Imma retake it and actually study

  • @dirtydozenzclash7333
    @dirtydozenzclash7333 9 лет назад +58

    I understand recursive quite well and I must say that this made no fucking sense.

  • @alexy.9306
    @alexy.9306 5 лет назад +4

    Feels good to know 900k + come here to study with me :)

    • @keela7324
      @keela7324 5 лет назад +1

      Can you help me w/ this? My question is find the explicit formula of 4,8,12,16,20

    • @pbates1693
      @pbates1693 4 года назад +3

      OwU no

  • @SaraphL
    @SaraphL 12 лет назад +1

    Link to respective playlist on khanacademy website, please!

  • @Sintrell1381
    @Sintrell1381 3 года назад

    Can anyone tell how is this finna keep me living or help in life

    • @parkjena1923
      @parkjena1923 3 года назад

      no, no one can cause it cant 😭

  • @sandwich8240
    @sandwich8240 5 лет назад +5

    Me, when I have a quiz on this tomorrow and still don't know absolutely anything

  • @yateeth10
    @yateeth10 5 лет назад

    This is gonna help me on my test Tomorrow because I don’t pay attention in class

  • @ZeqiG
    @ZeqiG 12 лет назад

    Have been doing this topic at college. We call them deductive and inductive definitions though rather than explicit and recursive :)

  • @nbshftr
    @nbshftr 4 года назад +3

    1:07 downhill from here

  • @citrusgem
    @citrusgem 3 года назад

    khan academy my beloved

  • @edgarperez8949
    @edgarperez8949 Год назад

    thanks for this explanation! the textbook I'm reading was not clear on the recursive definition!

  • @CaMaa456
    @CaMaa456 9 лет назад +32

    this did not help

  • @gracenoel373
    @gracenoel373 6 лет назад +37

    He makes this sound way too complicated.

  • @pbates1693
    @pbates1693 4 года назад +11

    Anyone here cause school got shut down

  • @notMysticz
    @notMysticz 7 месяцев назад +1

    shout out for the 8th graders at BASIS wallowing in regret

  • @barry2855
    @barry2855 Год назад

    love this guy

  • @thomaslandrey5691
    @thomaslandrey5691 9 лет назад +7

    This video is algebra 1 not precac so that's why you guys are confused. Its off topic

    • @basedandbananapilled2677
      @basedandbananapilled2677 7 лет назад

      Advanced Algebra, is when the formulas are learned

    • @elliptix9344
      @elliptix9344 6 лет назад

      I'm in pre algebra and we are learning this and I understand it now

    • @SequinBrain
      @SequinBrain 4 года назад

      It actually is precalc since it comes up again in Cal 2.

    • @fatguy7923
      @fatguy7923 4 года назад

      yeah i’m in algebra 1 rn

  • @dontplay2912
    @dontplay2912 6 лет назад

    U saved my life

  • @jenlin6913
    @jenlin6913 7 лет назад

    Thank you so much!

  • @galacticpopcorn9981
    @galacticpopcorn9981 4 года назад

    5:43 AERITH

  • @elliptix9344
    @elliptix9344 6 лет назад +1

    Okay. What I learned was
    An=An-1+d but the 1 is tiny it's the size of the n

  • @MehkaiManzano
    @MehkaiManzano 4 года назад

    omg thank you so much, I understand

  • @ChrisS-rp7yo
    @ChrisS-rp7yo 11 лет назад +9

    I only in seventh grade doing this

    • @RagtagNinja
      @RagtagNinja 11 лет назад +32

      sounds like younger by your English

    • @lemonsqueeZ96
      @lemonsqueeZ96 11 лет назад +9

      RagtagNinjaboy Not everyone on the internet speaks English their first language.

    • @calistakibak2287
      @calistakibak2287 10 лет назад +1

      Chris S Me too!!!

    • @Sabrinageerman
      @Sabrinageerman 10 лет назад +5

      wtf thats horrible i am so sorry

    • @elitetech7728
      @elitetech7728 10 лет назад +1

      hi_frwend i laughed so hard when i read this

  • @tanyonderrick168
    @tanyonderrick168 8 лет назад

    I understand how to do recursive just fine. and this was very different. I just wanted to know how to make an explicit function

  • @00777_
    @00777_ 4 года назад +9

    I have a math test today and I failed the practice test. Please help
    Edit: I failed 🧍‍♀️

    • @nomsai5663
      @nomsai5663 3 года назад +2

      LMAO

    • @HereForTheComments
      @HereForTheComments 3 года назад +1

      What happens now? Is there still hope for your mathematics journey?

    • @00777_
      @00777_ 3 года назад

      @@HereForTheComments school’s out 😎

    • @HereForTheComments
      @HereForTheComments 3 года назад +1

      @@00777_ Did you pass the grade?

    • @00777_
      @00777_ 3 года назад +1

      @@HereForTheComments yep I did well on all the other test this one just messed me

  • @shams...2417
    @shams...2417 Год назад

    Thanks 😊

  • @Trippie-cn8ot
    @Trippie-cn8ot 4 года назад +1

    YESS, we love just still not getting it

  • @RONOVLOGZ
    @RONOVLOGZ 7 лет назад

    Very helpful thank uou

  • @anilafariab
    @anilafariab 6 лет назад +1

    Do you guys have any tips for raising your math grade?

    • @elliptix9344
      @elliptix9344 6 лет назад

      Not really my grade rn is a 75 barley passing so just do your homework and sit next to the teacher in class like I do so you can be sure to hear what they say

  • @yuan3023
    @yuan3023 4 года назад +1

    Bruh i slept on my online class in math and i have a test later and watching this now

  • @aalokhardikar8342
    @aalokhardikar8342 4 года назад

    Thank you

  • @AngeRKang
    @AngeRKang 4 года назад +6

    failing math during quarantine squad?

  • @MarySilva-id1xe
    @MarySilva-id1xe 6 лет назад

    Ok so the explicit for me looks like f(n)=-6+5n and recursive was an=an-1+5 soooooo I'm hecka confused here and I have math first hour and I've been studying all weekend. And I was supposed to be celebrating my late bday today and ended up studying for my 5 FINALS TOMORROW....love that

  • @g-romeroflaviankaromero6335
    @g-romeroflaviankaromero6335 3 года назад +1

    Can you make a video on how to be good at math because my brain just don't agree with Math because its hard tnx.

  • @nomsai5663
    @nomsai5663 3 года назад

    The way there’s 1M views but only 2K likes, just shows how many times ppl had to re-watch it 😭

  • @iwant8907
    @iwant8907 5 лет назад

    I hate math but I love his videos

  • @543vantankhang5
    @543vantankhang5 3 года назад

    My mind is explode right now , but it's okay . I'll rewatch until i understand it .

  • @hoodiefreak9206
    @hoodiefreak9206 3 года назад +1

    I have a test on this today. We’ve been learning this since Monday and I still don’t understand

  • @danielmcdonald3642
    @danielmcdonald3642 7 лет назад

    thank you!

  • @tar0286
    @tar0286 7 лет назад

    well i understood.

  • @geraldaynyabyabin4289
    @geraldaynyabyabin4289 7 лет назад +1

    (k-1) what is the use of -1?

  • @seagull8758
    @seagull8758 5 лет назад

    Put it in double playback speed and you can learn everything about math in like 2 days

  • @josephmurillo3689
    @josephmurillo3689 5 лет назад

    This made it harder and made me confused

  • @kyrajohnson3029
    @kyrajohnson3029 10 лет назад +2

    Ok so I like how you worked but we're learning recursive a little bit differently. I'm totally lost with the recursive equation and I think I get your way but trying to turn your way into ours is giving me some difficulties.

    • @sonofjesus1464
      @sonofjesus1464 9 лет назад +2

      or ours into his way. He needs to work it the normal way :(

    • @sonofjesus1464
      @sonofjesus1464 9 лет назад

      +rusko dudesko And I major in Tardiness

    • @shosnow6824
      @shosnow6824 9 лет назад +1

      +Son Of Jesus Mom

  • @colinwhitlock5148
    @colinwhitlock5148 6 лет назад

    Why isn't there a single video on RUclips of someone doing a quadratic version of this?

  • @daniellelaraze7135
    @daniellelaraze7135 9 лет назад +1

    Thank you. I understand it now. But I have a question. I can't get the recursive formula of 5, -10, 15, -20, 25. I have tried this several times to get this formula. Can you help me?

  • @kazuohiroshi3923
    @kazuohiroshi3923 7 лет назад

    thx man

  • @victorstorm2880
    @victorstorm2880 11 лет назад

    so you shows ak-1, but what if the formula says ak+1, what does that mean? the next term? if its recursive how can u being going off of the next term?

  • @axanzy
    @axanzy 4 года назад +3

    That's crazy who here cause of corona?

  • @hannahellkitty
    @hannahellkitty 8 лет назад

    What if you don't have your first term or difference but you have the number of terms?

  • @euniceruta3260
    @euniceruta3260 3 года назад

    I kinda understand it but how to get the next term when the differences are not the same?

    • @GraceandBeth
      @GraceandBeth 2 года назад

      haha i’m a year late but if they’re not the same then it’s not a arithmetic formula

  • @lorenaronquillo
    @lorenaronquillo 11 лет назад +1

    There are no bad explanations, only students who refuse to ask when they don't understand something. ;)

  • @numba1depecher
    @numba1depecher 2 года назад

    had to turn in a test today with literally nothinf kn the first page cus i cant do thus yet 😭

  • @doretheadillings8007
    @doretheadillings8007 7 лет назад +6

    Wha .. ? WHAAA ??

  • @wizard-cs2st
    @wizard-cs2st 3 года назад

    5:26
    *brown*
    khan: "that's not an attractive color, let me write this in.."
    *WHITE*

    • @PlayaRiptide
      @PlayaRiptide 3 года назад

      I don't think he meant it like how you think he meant it

  • @gumbosunrise1825
    @gumbosunrise1825 5 лет назад

    Ay thanks for the help but pretty sure i still bombed the test

  • @anthonymarlow2269
    @anthonymarlow2269 7 лет назад +6

    You have a high IQ

  • @user-ip9fp8ug5y
    @user-ip9fp8ug5y 4 года назад

    Question: is there always a -1 in the (k-1) part or what?

  • @uyenchang9062
    @uyenchang9062 9 лет назад

    what is it mean "one less than the term we add"..?

    • @ellieb8627
      @ellieb8627 9 лет назад

      To find the mean you add all the terms together and then divide by the number of terms

  • @akshayappan6526
    @akshayappan6526 9 лет назад

    Why does he put a (k-1) after the three?
    Please answer.

  • @95MarioKaci95
    @95MarioKaci95 6 лет назад

    What book are u using??? can someone tell me?

  • @kennedysaniah
    @kennedysaniah 7 лет назад

    He sounds like Young Don the sauce God

  • @somewhiteguy1945
    @somewhiteguy1945 4 года назад +1

    hold up, this is pre-calucus?? Im learning this is algebra...

  • @malloryscinematography7021
    @malloryscinematography7021 2 года назад

    I gotta test Tommarow and I’m not consuming any of this information

  • @imagination7710
    @imagination7710 8 лет назад

    Could I not say for the second one; 3k + (k-1)?

  • @TheMacbebe101
    @TheMacbebe101 10 лет назад +8

    Lol what?

  • @MacJunkyFlips
    @MacJunkyFlips 7 лет назад

    what. this is nothing like in school. now i cant do anything while im sick

  • @Dattaya108
    @Dattaya108 12 лет назад

    /math/trigonometry/seq_induction

  • @Boss_Cheese
    @Boss_Cheese Год назад +1

    Where did they (k-1) come from 😭

  • @poptarts1455
    @poptarts1455 5 лет назад

    Is previous term always -1???