Distance between planes | Vectors and spaces | Linear Algebra | Khan Academy

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  • Опубликовано: 26 авг 2024
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    2010 IIT JEE Paper 1 Problem 51 Distance Between Planes
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Комментарии • 54

  • @ばにゃにー
    @ばにゃにー 11 лет назад +21

    Just finished all 144 videos and I wanted to thank you for teaching me. It was definitely interesting, and I'll be looking forward to any future videos.

  • @anuragmishra3227
    @anuragmishra3227 6 лет назад +11

    I am an IIT JEE 2020 aspirant. Your videos have helped me a lot.
    Thank You.

  • @markeppard3698
    @markeppard3698 6 лет назад +12

    Perhaps someone could clarify this... Starting at 11:08 Sal keeps saying "lets find the distance between the two planes" and continues looking for "the distance" for the remainder of the video.
    I'm confused because it gives this distance in the initial problem. After reading the questions and comments, everyone else seems equally confused, and none of their explanations are correct either.
    Going back to Sal's Normal Vector From plane Equation Video: ruclips.net/video/gw-4wltP5tY/видео.html at 9:18 he explains that the d-value shifts the plane, and doesn't change its tilt.
    Isn't this the same as the distance in this situation since the d-value of the blue plane in the equation is 0 in the equation
    -x +2y -z=0 (before he multiplies both sides by -1)?
    Since the equation of the blue plane in this video is found to be -x +2y -z=0 (before he multiplies both sides by -1), it makes sense that the equation for the red plane can be written as x -2y +z = 6, since it's a distance of 6 units up from the blue plane, however, it contradicts with the given distance of square root (6), which is approx. 2.45.
    Since the planes are parallel, doesn't the distance between them remain constant?
    What is the actual distance?

    • @pranavchat141
      @pranavchat141 5 лет назад +5

      I think you'd probably have figured it out, since it's been more than a year but for the ones following this thread, I mention this:
      Distance between two planes, Ax + By + Cz = D1 and Ax + By + Cz = D2 is not just |D2- D1| but
      |D2- D1|/ sqrt of (A^2 + B^2 +C^2).

    • @johnhyde
      @johnhyde 4 года назад +1

      Pranav Chaturvedi Thanks for this. I was very confused after his obviously incorrect statements at the end of the video; this makes it pretty much clear. I'm a bit disappointed that he hasn't fixed this... 😔

  • @fashionvella730
    @fashionvella730 11 месяцев назад +1

    Finally finished the whole linear algebra playlist. Math is not my major but just because of khan's way of explaining math I fell in love with math. The way you teach I have never learned this way in my whole life. I was just solving questions by remembering formulas, but you changed my whole perspective for math. Now going to learn calculus from your amazing lectures.
    Thank you sooooooooooooo much Sal
    😍😍😍😭

  • @bikashthapa7316
    @bikashthapa7316 6 лет назад +13

    finally i have completed whole playlist

    • @yonghuiliew8066
      @yonghuiliew8066 4 года назад

      Thank god

    • @Pieruh
      @Pieruh 3 года назад

      Im just curious but how long did it take you to complete? Im starting out myself

    • @maxwang2562
      @maxwang2562 Год назад

      @@Pieruh one a day would be half a year.

  • @Elmaxsivu
    @Elmaxsivu 2 года назад +3

    Finished 144 videos... MY brain hurts, but I would like to thank you a lot.

  • @123mister321
    @123mister321 4 года назад +2

    It was a long ride but I finally made it to the end! Thanks for these awesome Algebra videos!

  • @goclbert
    @goclbert 2 года назад +1

    If anyone is wondering where to go now that you've finished the playlist, I'd recommend looking up the MIT 18.06 course on linear algebra. Try to do the first two quizzes and if you have any trouble, watch the corresponding MIT lecture videos. Once you feel comfortable with those, finish out the rest of their linear algebra lectures and try the final exam and quiz.

  • @redteamdarkspear
    @redteamdarkspear 13 лет назад +1

    I just got to the symmetric equations in my calculus tonight. I know they're not actual calculus equations but I'm glad to see that they're used in other subjects as well

  • @lhyx1990
    @lhyx1990 13 лет назад +1

    is it the last video for linear algebra? can't believe i finished the course within 2 weeks.

  • @willwei98
    @willwei98 9 лет назад +6

    Can't you just cross (2,3,4) and (3,4,5) without finding random vectors using points like a = 2i + 3j + 4k and b = i + j + k
    Wouldn't that get you the normal of the plane as well?

    • @ArnavBarbaad
      @ArnavBarbaad 8 лет назад +1

      +Will Wei Omg no! Those are the position vectors for points on the plane. Those are NOT a vector on the plane (parallel to the plane). If you cross them, you would get a vector perpendicular to the position vectors, not to the plane itself!

    • @ArnavBarbaad
      @ArnavBarbaad 8 лет назад

      +Will Wei Hold on, I don't fully understand what you're trying to say

    • @hmz01_
      @hmz01_ 6 лет назад

      no it would get u a random normal that u cant use

    • @yonghuiliew8066
      @yonghuiliew8066 4 года назад +1

      Guys guys....(2,3,4) and (3,4,5) are the scaling vectors of the lines. So hes right

    • @Aman_iitbh
      @Aman_iitbh Год назад

      @@yonghuiliew8066 yes he is,right

  • @mea852456
    @mea852456 11 лет назад +3

    Brilliant

  • @Daniel-to5jd
    @Daniel-to5jd 5 лет назад +1

    all Linear algebra course done

  • @alinapostol2230
    @alinapostol2230 3 года назад

    Just completed the playlist. Thank you for everything Sal!

  • @Evdis
    @Evdis 7 лет назад +2

    From the bottom of my heart and my now very tired brain: THANK YOU for this playlist.

  • @wanx891
    @wanx891 7 лет назад

    when Khan did this, to find vector N * the other part=0, can I use a different vetor(maybe(2,3,4)) to also be =0 and slove it?

  • @kcwilliamson50
    @kcwilliamson50 7 лет назад +1

    Will Wei is right and Arnav Barbaad is wrong. The denominators are the components of the direction vectors for the lines, not the position vectors for a plane. Sal could have just used them instead of working so hard.

  • @coach41lebron
    @coach41lebron 11 лет назад

    Just a suggestion Sal. Could it be at all possible that you include in the description or as links the related videos you talk about. When you mention them in videos they arent always easy to find. Only if its not too much trouble

  • @sechokito
    @sechokito Месяц назад

    finished finally

    • @sechokito
      @sechokito Месяц назад

      graph theory is next.

  • @greedskith
    @greedskith 4 месяца назад

    SAME QN IN WBJEE 2023 WAS JUST SOLVING IT AND GOT STUCK, 😄

  • @yangyuew9177
    @yangyuew9177 3 года назад

    I think he meant the distance between the two closest points should be sqrt(6) at the end of the video

  • @loganmanuel-mcgarry9068
    @loganmanuel-mcgarry9068 2 года назад

    just to clarify: he is solving for ‘d’ in the equation of the first plane, right? because distance is given, but the ‘d’ value of the first is not.

  • @konanuk
    @konanuk 11 лет назад

    You rock, Sal

  • @leadtoexemplify
    @leadtoexemplify 3 года назад

    To find the distance all you need is a point and the plane equation. You found the point already at the beginning. I don't understand the need to figure out equation of another plane. of course it proved that plane containing other two lines is parallel to the plane in question. Did I miss something?

    • @Insolent1
      @Insolent1 2 года назад

      Sort of, you don't need to find the equation of the second plane, but unless you want to find the answer in terms of A, you have to solve for A before you solve for |d| (which, IMO, should really be |D| as part of the plane equation Ax+By+Cz=D), = |A-1-sqrt(6)*sqrt(A^2+5^2)|
      Although, it's easier to use a vector between (any) two unique points with one from each of the lines (e.g. the vector from (1,2,3) on one line to the (2,3,4) on the other = [1,1,1]) and dot it with the normal vector from the plane equation, which must equal 0 since they are orthogonal (or is it perpendicular? I already forgot...), i.e. [1,1,1] dot [A,-2,1] = 0 -> A*1+(-2)*1+1*1 => A = 1
      OR
      Take that same vector between the two lines, e.g. [1,1,1] and knowing that it is parallel with the defined plane and, therefore, any point on the plane Ax+By+Cz= D also equals Ax_2+By_2+Cz_2, which means Ax+By+Cz= A(x+ the x part of the vector)+B(y+the y part)+C(z+the z part) => Ax -2y + z = A(x+1) -2(y+1) + (z+1) -> 0 = A -2 +1 -> A = 1

  • @DelphianSociety
    @DelphianSociety 12 лет назад +1

    Amazing that this is an IIT question. Isn't this US college material?

  • @chenmargalit7375
    @chenmargalit7375 4 года назад

    I dont get it. If they say the distance is square root of 6 then: 1. Why did we have to calculate it ? 2. Why did we get 6 if they say its square root of 6 ? whats the meaning of the difference between the given they provided and the answer we found ?

  • @Chriscx
    @Chriscx 10 лет назад +1

    2nd what daniel ong said. Distance between 2 planes is square root of 6 but the absolute distance is 6??? really confused

    • @Titurel
      @Titurel 9 лет назад +1

      The "d" is not "distance it is a constant. Just make it G and you'll understand better

  • @LondonWalkability
    @LondonWalkability 13 лет назад

    you are awesome :)

  • @Phagocytosis
    @Phagocytosis 11 лет назад

    All 144 videos? That must only be the videos in some topic, because even four months ago, there were thousands of videos on Khan Academy. Just in case you missed that :) anyway, good going!

    • @Kornchipzzz
      @Kornchipzzz 5 лет назад

      144 videos on just linear algebra :)

  • @YAMIKAN99
    @YAMIKAN99 11 лет назад +3

    I dont get it. Distance between 2 planes is square root of 6 but the absolute distance is 6??? really confused

  • @dravidr007
    @dravidr007 13 лет назад

    i am still on about vid 20 on this set....hope to get here soon!!!!!!!!!!!!

  • @piglink10
    @piglink10 6 лет назад

    If both planes are the same equation, don't they share the exact points ?

    • @AleksandrSerov-rn2cn
      @AleksandrSerov-rn2cn 4 года назад +1

      As you can see at the end, the D value of both equations is different

  • @abhinavchauhangujjar6456
    @abhinavchauhangujjar6456 6 лет назад

    what if one plane is tilted towards other

    • @hooligan1717
      @hooligan1717 5 лет назад +5

      If tilted, they will eventually intersect and the distance between them would be zero.

  • @and1fer
    @and1fer 10 лет назад

    how did (x-2y+z = 0 become x-2y+z = d) and where did A disappear?

  • @drumnub
    @drumnub 7 лет назад

    There seems to be no audio for me. Is anyone else having the same issue?

  • @bopeng9504
    @bopeng9504 8 лет назад +11

    horrible explanation.