Ways to Visualize Multiplying Negative Numbers

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  • Опубліковано 3 жов 2024

КОМЕНТАРІ • 29

  • @magma90
    @magma90 2 дні тому +29

    There is an amazing greentext that gives an answer to negative*negative
    > turn around
    > turn around again
    > wtf I’m facing the same direction
    Why doesn’t positive*positive=negative
    > don’t turn around
    > don’t turn around again
    > wtf I’m facing the same direction

    • @nio804
      @nio804 День тому +3

      That even works for complex numbers, except i is a 90-degree turn.

    • @EggZu_
      @EggZu_ День тому +3

      this is the exact post i thought about when i saw this video title lol

    • @theunholybanana4745
      @theunholybanana4745 14 годин тому

      @@nio804 this is why it's such a good analogy, it works exactly how complex multiplication works
      z₁=a*e^(iθ), z₂=b*e^(iΦ)
      z₁*z₂=a*b*e^(i(θ+Φ))

    • @hydrogenbond7303
      @hydrogenbond7303 8 годин тому

      I think that's even better explanation! In a sence, that's the "geometry" explanation I was looking for. Thanks!

  • @TymexComputing
    @TymexComputing 2 дні тому +10

    I haven't clicked UA-cam for ten hours and here you are on the main page! Best wishes and health wishes from Poland! Thank you for your job in propagating nonconformal mathemagical thinking in the world Domotro, its a real talent to polish up!

  • @litigioussociety4249
    @litigioussociety4249 2 дні тому +5

    I've heard about money analogies before, but the graph is a great explanation.

  • @Domotro
    @Domotro  2 дні тому +9

    Let me explain some assorted ways to visualize why multiplying two negative numbers results in a positive number... Also make sure you've checked out my latest main episode on my @ComboClass channel: ua-cam.com/video/pylw9t4j6bM/v-deo.html

  • @samclare3765
    @samclare3765 День тому +5

    Here's an idea to explain this:
    Obviously multiplying can be thought of as shorthand for adding the number to itself several times. So for example 2*3 = 2+2+2 = 6.
    So -2*3 must be -2 + -2 + -2 = -2 - 2 - 2 = -6. It's 3 lots of the amount "-2" ie 3 times -2.
    So what about -2 * -3. It's -3 lots of -2. It's hard to visualise but one thing for sure is it cannot be the same as "3 lots of -2". So this expands out to:
    - (-2) - (-2) - (-2) = 2 + 2 + 2 = 6.
    It now looks like the more easily understood "negative minus a negative gets more positive", repeated. You're negating a negative several times over, so the number must go positive.

  • @lesnyk255
    @lesnyk255 День тому +3

    As it was explained to me way back in junior high (what we now call "middle school"): imagine filming a car pulling into your driveway, in the Forward (i.e., + ) direction. If you play the video back in the normal + direction, you see a car entering your driveway in the + direction. Postive x Positive = Positive. If you play the video in reverse ( i.e. in the - direction), you'll see the car backing out of your driveway: Positive x Negative = Negative. Same if you film the car backing out of the driveway (- direction) & play it back normally (+ direction): Negative x Positive = Negative. But if you reverse the video of the car backing out of your driveway, it wlll appear to be driving forward: Negative x Negative = Positive. QED.

  • @robinbeckford
    @robinbeckford День тому +3

    New furniture? I like what you've done with the place.

  • @ohmisterjeff
    @ohmisterjeff 2 дні тому +4

    Over 4 minutes before something hit the ground... New record!

  • @TheMagicFellow
    @TheMagicFellow 2 дні тому +1

    I've always seen negatives in the way you describe it towards the end. Binary, or like a switch, which can be flipped by a negative.

  • @hallucinogender
    @hallucinogender День тому

    In language, double negatives are interesting because a deliberate double negative carries different semantic information than the equivalent positive. "It's not inedible", in most contexts, is likely to suggest that you can technically eat it but you really don't want to.

  • @mandrew31
    @mandrew31 2 дні тому +1

    Thank you, Big Joel But Mathematician.

  • @ssj3gohan456
    @ssj3gohan456 2 дні тому +1

    came here purely for the clock battery throw

  • @c_b5060
    @c_b5060 2 дні тому

    I learned that division was subtraction over and over. And that multiplication was addition over and over.

  • @WalterHildahl
    @WalterHildahl День тому

    Multiplying two negatives makes a positive. But multiplying two positives do not make a negative.

  • @beerkegaard
    @beerkegaard 15 годин тому

    Because when me and my wife are both negative, I’m positive we’re going to fight

  • @timwhite7127
    @timwhite7127 День тому

    I didn't know it could be done but I think this tutorial just removed knowledge from my head...

  • @anglaismoyen
    @anglaismoyen 2 дні тому

    I would find it a lot easier to teach this if subtracting a number from (i.e. adding a negative to) a negative number didn't become more negative.

  • @jhonbus
    @jhonbus День тому

    Dude why do we always gotta go through this math lesson just gimme my meth!

  • @sr6424
    @sr6424 21 годину тому

    Say we live in a world where multiplication is banned but division isn't. To perform any multiplication you need to divide by the reciprocal of one of the numbers.. Instead of multplying 3 times 2 you divide 3 by 1/2 which is ,5. when you divide you can start cancelling out. the -ve example similar to above -3 times -2 becomes -3/-0.5. The two negative signs cancel.

  • @HamishHaughey
    @HamishHaughey День тому

    So if I owe £100 to a loan shark, and £100 to a dealer, they actually owe me £10000? Why didn't they teach me this in school?!

    • @ramunasstulga8264
      @ramunasstulga8264 22 години тому

      When C level students pretend to understand math be like 💀

  • @TymexComputing
    @TymexComputing 2 дні тому +1

    7:30 that line is straight in their own world because the axes are perturbed :)
    -1 reminds me of imaginary part of complex numbers, of parity symmetry, of Hyperions, mesons, fermions in their special symmetry groups and quaternions and that two imaginary units 'i' in 2D representation multiplied by itself give -1 and the same gives -i and that quadratic equation always have 2 solutions :).
    I wonder how does quaternion multiplication look like in 3D part :)

  • @_abdul
    @_abdul День тому

    ...wtf I'm facing the same direction.

  • @jmwild1
    @jmwild1 2 дні тому

    Here's a double negative: I can't not enjoy these videos. Informational and funny.

  • @MatematicaRio
    @MatematicaRio 2 дні тому +1

    First!