Linear transformation examples: Rotations in R2 | Linear Algebra | Khan Academy

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  • Опубліковано 18 січ 2025

КОМЕНТАРІ • 60

  • @abhijit-z
    @abhijit-z 10 років тому +27

    I never used to understand this but now after watching this video, I've clearly understood it.

  • @saferehman8234
    @saferehman8234 5 років тому +9

    Finally a channel that does eveything in a dark background xD

  • @norwayte
    @norwayte 15 років тому +3

    I have read in a lot of textbooks different explanations of rotations - and yours is one of the best.
    Still waiting for
    - planes, points, lines and how they can relate to each other
    - Hessesche normal form
    - circles, ellipses and spheres
    - economic examples for matrix-multiplications
    - more on determinants...Sarrus....all the juggling with matrices to calculate real problems (examples)
    Keep on going.

  • @TheMrlightswarm
    @TheMrlightswarm 10 років тому +21

    I have a wonderful professor that clearly demonstrated this concept of coefficient matrices that is valid for rotational linear transformations but man Sal, you're the man for solidifying that knowledge! You've inspired me to teach and share the gift of knowledge and am currently pursuing a career in teaching mathematics! Thank you for all the help Sal. I want to let you know that your videos have left a positive impact in your audience's lives :).
    ~Cheers!

    • @Anders.B.
      @Anders.B. 6 років тому +1

      Jay P you just brightened my afternoon with your positive attitude. Hope you are having fun teaching!

  • @ryanmonte
    @ryanmonte 14 років тому +1

    For anyone that might have been confused by this... at around 1:55 when Sal says "what do we have to do to show that this is a linear combination?" I'm pretty sure he meant "what do we have to do to show that this is a linear transformation?"

  • @apanapane
    @apanapane 14 років тому +2

    This video helped me immensely to understand rotation matricies. I thank you, sir.

  • @JerryChenish
    @JerryChenish 10 років тому +3

    I was looking for this for hours.
    Thank you for the explanation.
    It's pretty clear and I like your teaching vedio.

  • @nwind27
    @nwind27 12 років тому +1

    this is one of the super ultra clear lesson sal!!

  • @Cheech550
    @Cheech550 15 років тому

    Fantastic Video. If you have struggled to fully understand transformations in the past, then this video will ensure you have a keen working knowledge of Linear Transformations

  • @spider853
    @spider853 15 років тому

    Thanks! Now its clear to me where those matrices are from... I'm programing 2D/3D games for 2 Years and never tried to figure out where did those transformation vectors comes.

  • @aliusman9693
    @aliusman9693 Рік тому

    thank you so much i was worried about these types of questions

  • @WateryIce54321
    @WateryIce54321 9 років тому +1

    Always such fantastic explanations.

  • @anitharathod4770
    @anitharathod4770 4 роки тому

    I didnt understand this topic in class....but now feeling its a really easy topic

  • @AmarUllah-n2k
    @AmarUllah-n2k 2 місяці тому

    Thank you Sal

  • @GladnessGeorge-g5r
    @GladnessGeorge-g5r Рік тому

    Thanks alot for the amazing 😻😻 lesson it means a lot to me🎉🎉

  • @zacklantz8181
    @zacklantz8181 10 років тому

    At last I understand this! I was pretty frustrated at first... about 15 videos later and I think I've got it!

  • @edoardolaspada
    @edoardolaspada 6 років тому

    Thank you very much, very clear explanation

  • @LeVraiment
    @LeVraiment 8 років тому

    Thank you for this video. I have a presentation on rotation transformation the next day. I must say this video has given me the right knowledge to present in class. Thanks a million times

  • @FlareGunDebate
    @FlareGunDebate 5 років тому

    This is a great description of linear transformation. Thank you very much.

  • @vexedev
    @vexedev 11 років тому +1

    I love you man!

  • @Lena-si5fk
    @Lena-si5fk 5 років тому

    Thanks, this video was very helpful! :)

  • @arwaelkasaby471
    @arwaelkasaby471 7 років тому

    Really Thank you very much :3

  • @KAFA2020
    @KAFA2020 7 років тому

    Awesome

  • @s0m0c
    @s0m0c 13 років тому

    Thank you very much

  • @ddsmax
    @ddsmax 7 років тому

    when u told us to ponder i started thinking bout vortexes and poverty, and now i own a million dollar business. atleast in my head.

  • @THT1991
    @THT1991 14 років тому

    @ryanmonte thx for bringing that up! i was hoping someone could make it clear for me and there you are =)

  • @s0m0c
    @s0m0c 13 років тому

    Gracias.

  • @00165530
    @00165530 14 років тому

    Thanks!

  • @Waranle
    @Waranle 15 років тому

    Another great video

  • @TheJagdNinja
    @TheJagdNinja 12 років тому

    So much better than my thick accented Russian Prof

  • @SkubJohn
    @SkubJohn 8 років тому

    Thank you

  • @Morlich209
    @Morlich209 6 років тому

    Does the matrix also apply to rotations in the clockwise direction?

  • @aidenmurphy9924
    @aidenmurphy9924 8 років тому +4

    You use -sin because your angle goes past pi/2. What if 0 < angle < pi/2? Then it would be [cos sin, sin cos]?

    • @NicoDevs1998
      @NicoDevs1998 6 років тому

      Since e1 is always pointing up (since it is a basis vector), and since we rotate counterclockwise, e1 will never be in 0 < angle < pi/2. In the case where you over extend the angle, the angle will be greater than 270, the math will work out; for instance, the - sin (315) is positive sqrt(2)/2.

  • @Myrslokstok
    @Myrslokstok 13 років тому

    Love 6:24 where he states why.

  • @HappyKitya
    @HappyKitya 28 днів тому

    5:48 16:40

  • @anurajdixit9707
    @anurajdixit9707 8 років тому

    how to check linearity of rotation operators?

  • @marabi4
    @marabi4 4 роки тому

    why is the hypotenuse length 1?

  • @fourelementmagicring
    @fourelementmagicring 9 років тому

    what if i want to rotate it at certain point?

  • @sagarjagad6235
    @sagarjagad6235 8 років тому

    Tysm sir

  • @yamacyurtsever7201
    @yamacyurtsever7201 6 місяців тому

    Love you

  • @karimkhan1312
    @karimkhan1312 11 років тому

    You are excellent

  • @totoplopp6630
    @totoplopp6630 4 роки тому

    Great information but please improve legibility, this is a mess.

  • @spdyeric
    @spdyeric 13 років тому

    @Roqu3ntin make it negative

  • @junmun5035
    @junmun5035 4 роки тому

    For the 26 people that disliked this vid... good luck because no ones gonna break it down like this for you.

  • @Judobrinez
    @Judobrinez 8 років тому +6

    wat?

  • @alexqiu3782
    @alexqiu3782 7 років тому

    The pace is too slow, good video though

  • @thentust
    @thentust 8 років тому

    Why other films show the opposite sign of the Sin terms?
    but they explain also reasonable, but why has this difference?

    • @thentust
      @thentust 8 років тому

      No,I was wrong. This one is to rotate the point,and the other one is to rotate the whole axises without the point.
      and cause the signs difference.

  • @Zerpentile93
    @Zerpentile93 12 років тому

    Thank you. Now I do not have to read my poorly written fucking math book. :)

  • @melesebekele9015
    @melesebekele9015 9 років тому

    m

  • @Dreaming-11
    @Dreaming-11 7 років тому

    This is not a proper demonstration, you skipped some important passages.

  • @Jiao12
    @Jiao12 8 років тому +1

    Helpful as but could be much better. Stop being so ponderous!!

  • @Gandalfbaws
    @Gandalfbaws 10 років тому

    WTF!

  • @DacoTaco
    @DacoTaco 14 років тому

    @TheBatchGuy my math teacher was like that.
    i miss him so much :(

  • @avishkadilshan1713
    @avishkadilshan1713 Рік тому

    Thank you!