• Zagorath
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    2961 month ago

    Fake and gay.

    No way the engineer corrects the mathematician for using j instead of i.

    • LeFrog
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      531 month ago

      As an engineer I fully agree. Engineers¹ aren’t even able to do basic arithmetics. I even cannot count to 10.

      ¹ Except maybe Electrical engineers. They seem to be quite smart.

      • @Chakravanti@monero.town
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        21 month ago

        That’s hilarious. You’re not seeing what’s going on backwards just like that (as I point at the point going nowhere shitty) in an equation that is finding as many clAEver ways to say something you actually not caring about talking about.

        That’s like, "How many time van express the only thing that van’t be done until the 'verse itself tries to do what can’t be done and sever your…

        …Oh, I see…you don’t have ([of course, because you can’t have to give {is}) nothing)] to give.

        Unable to sea time doesn’t mean we can’t see(k)ER the mAETh.ac(k).cc(k).08

        The only thin(g):(k) that doesn’t ever be never, is not at alla hack(g)in(g).G your lackthereof to divi…

    • Kogasa
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      201 month ago

      The mathematician also used “operative” instead of, uh, something else, and “associative” instead of “commutative”

      • Zagorath
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        31 month ago

        “operative” instead of, uh, something else

        I think they meant “operand”. As in, in the way dy/dx can sometimes be treated as a fraction and dx treated as a value.

          • Zagorath
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            21 month ago

            The operand is the target of an operator

            Correct. Thus, dx is an operand. It’s a thing by which you multiply the rest of the equation (or, in the case of dy/dx, by which you divide the dy).

              • Zagorath
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                11 month ago

                You’re misunderstanding the post. Yes, the reality of maths is that the integral is an operator. But the post talks about how “dx can be treated as an [operand]”. And this is true, in many (but not all) circumstances.

                ∫(dy/dx)dx = ∫dy = y

                Or the chain rule:

                (dz/dy)(dy/dx) = dz/dx

                In both of these cases, dx or dy behave like operands, since we can “cancel” them through division. This isn’t rigorous maths, but it’s a frequently-useful shorthand.

                • @Chrobin@discuss.tchncs.de
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                  21 month ago

                  I do understand it differently, but I don’t think I misunderstood. I think what they meant is the physicist notation I’m (as a physicist) all too familiar with:

                  ∫ f(x) dx = ∫ dx f(x)

                  In this case, because f(x) is the operand and ∫ dx the operator, it’s still uniquely defined.

  • PM_ME_VINTAGE_30S [he/him]
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    1561 month ago

    Wait bottom mathematican is using j=√-1 instead of i and not the engineer? Because I’m EE gang, and all my homies use j.

    • GandalfTheDumb
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      651 month ago

      That part also got me really confused. All the mathematicans I know use i while engineers use i or j depending on the kind of engineer. I’ve never seen a Pikachu engineer using anything other than j.

      • @ryedaft@sh.itjust.works
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        31 month ago

        OPs boyfriend is obviously an i engineer and hates j engineers. No one can stay angry at mathematicians - engineers on the other hand…

              • @Jarix@lemmy.world
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                51 month ago

                I clicked your link, I barely made it out of highschool so I have no idea what any of it means, but I like reading things I shouldn’t understand anyway, sometines it’s so interesting even without understanding.

                So I thank you!

                • @Klear@sh.itjust.works
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                  31 month ago

                  Quaternions are the closest we get to lovecraftian horror in real life.

                  Four dimensional and mostly imaginary, they were carved into a stone bridge by a crazy mathematician in a fit of madness, Lord Kelvin called them “unmixed evil”, and the Mad Hatter from Alice may have been inspired by them.

                  Also they have been a curiosity at best for a long time, despite the efforts of a secret Quaternion Society, but they suddenly blew up in usefulness in modern times as they happen to be an easy and fast way for computers to describe rotations in 3D space, so they’re everywhere.

                  Yeah, lovecraftian as shit.

        • CodexArcanum
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          1 month ago

          It gets worse actually. You can define a number system using any power of 2 amount of i-like units in a similar relationship to quaternions using the Cayley-Dickson construction

          Fascinatingly, you lose some property of the algebra at each step. Quaternions aren’t commutative: ABC != CBA. Octonians aren’t associative: (AB)C != A(BC). Once you get into 16 i’s with subscripts, it really gets crazy.

          (Also, I just got the joke. Damnit @HappyFrog@lemmy.blahaj.zone your serious answer threw me off!)

    • @grysbok@lemmy.sdf.org
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      111 month ago

      [Lapsed] mechanical engineering gang checking in. I was also surprised. Though, tbh, I think it came down to personal preference of the professor more than field-wide consensus.

    • @bitcrafter@programming.dev
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      1 month ago

      Imagining your death. :P

      But seriously, it’s perfectly sensible when remember that i is just the mathematical representation of “left turn”, just like -1 is the mathematical representation of “go backwards”-- and as we know, two left turns sends you backwards. So think about this triangle in the following way:

      Imagine you are a snail, starting at the origin. Now imagine that you walk forward 1 step along the horizontal line. Then you turn 90° to the left to start walking along the vertical line, but then, because you need to walk i steps along this line you take another 90° turn to the left, which means that you are now walking backwards and you end up back at the origin. How far away from the origin are you? Zero steps.

  • Avicenna
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    1 month ago

    operative?

    Also mathematicians use i for imaginary, engineers use j. The story does not add up. I have never seen a single mathematician use j for imaginary.

    • @sartalon@lemmy.world
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      91 month ago

      As an EE, I used both. Def not a mathematician though. Fuck that, I just plug variables into programs now.

      • Avicenna
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        1 month ago

        Interesting I never saw j from a maths person. Friends (from a decade ago!) in electronics eng dep said they use j because i was reserved for current. perhaps the latter depends on the department.

        • @Chakravanti@monero.town
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          11 month ago

          j is pretention when a math doer does it. j is for engineers and you don’t even understand the bubble ratio filtering equation let alone be asking to envision what temp you did the mAEth in.

          You got lost in the number of letters instead of realizing the MeTowel’s important presence til that EOTU moment of that manufa turing of Big Black Goles you get to watch it all happen again as Thanos facepalms.

  • cub Gucci
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    301 month ago

    As a physicist I can’t understand why would anyone complain about a +jb or $\int dx f(x)$. Probably because we don’t fuck

      • cub Gucci
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        1 month ago

        Heeyy… So when you need to express something more, well, delicate than just code, you need to use math symbols. For that you can use tex expressions. Modern markdown supports it: just copy and paste the $…$ part into any render engine

  • @laserm@lemmy.world
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    261 month ago

    Why would a mathematician use j for imaginary numbers and why would engineer be mad at them?

    • dustycups
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      101 month ago

      I think it might be the wrong way around: Engineers like to use j for imaginary numbers because i is needed for current.

    • ThePuy
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      81 month ago

      Mathematicians are taught to be elastic with notation, because they tend to be taught many different interpretations of the same theory.

      On the other hand engineers use more strict and consistent notation, their classes have a more practical approach.

      Using the same notation makes it faster to read and apply math, a more agile approach helps with learning new theories and approaches and with being creative.

  • @Phoenix3875@lemmy.world
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    241 month ago

    I think rather d/dx is the operator. You apply it to an expression to bind free occurrences of x in that expression. For example, dx²/dx is best understood as d/dx (x²). The notation would be clear if you implement calculus in a program.

      • ඞmir
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        21 month ago

        If you use exterior calculus notation, with d = exterior derivative, everything makes so much more sense

    • @yetAnotherUser@discuss.tchncs.de
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      41 month ago

      I just think of the definition of a derivative.

      d is just an infinitesimally small delta. So dy/dx is literally just lim (∆ -> 0) ∆y/∆x. which is the same as lim (x_1 -> x_0) [f(x_0) - f(x_1)] / [x_0 - x_1].

      Note: ∆ -> 0 isn’t standard notation. But writing x -> 0 requires another step of thinking: y = f(x) therefore y = ∆f(x) = f(x + ∆x) - f(x) so you only need x approaching zero. But I prefer thinking d = lim (∆ -> 0) ∆.