• credo@lemmy.world
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    8 hours ago

    I don’t remember all my geometric rules I guess, but can an arc, intersecting a line, ever truly be a right angle? At no possible length of segment along that arc can you draw a line that’s perpendicular to the first.

    • filcuk@lemmy.zip
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      7 hours ago

      An infinitely small segment of the arc can be.
      Geometrically there isn’t a problem. If you draw a line from that point to the center of the arc, it will make it clearer.

      • credo@lemmy.world
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        6 hours ago

        I guess if we define it as a calculus problem, I can see the point…

        I didn’t mean to pun but there it is and I’m leaving it. Any way, there is no infinitely small section that’s perpendicular. Only the tangent at a single (infinitely small) point along a smooth curve, as we approach from either direction. Maybe that’s still called perpendicular.

    • pooberbee (they/she)@lemmy.ml
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      7 hours ago

      A right angle exists between the radius of the circle and the line tangent to the circle at the point that the radial line intersects it. So we can say the radius forms a right angle with the circle at that point because the slope of the curve is equal to that of the tangent line at that point.

    • AnarchoEngineer@lemmy.dbzer0.com
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      9 hours ago

      Perhaps this is just a projection of a square from a non-Euclidean space in which the lines are in fact straight and parallel.

      I think the 2D surface of a cone (or double cone) would be an appropriate space, allowing you to construct this shape such that angles and distances around geodesics are conserved in both the space itself and the projected view.

      This shape in that space would have four sides of equal length connected by four right angles AND the lines would be geodesics (straight lines) that are parallel.

    • Angry_Autist (he/him)@lemmy.world
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      8 hours ago

      there is no definition that someone can’t fuck up, that’s the point of this exercise, not to find a perfect definition

      But as usual 70% of you miss it

      • Zorque@lemmy.world
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        7 hours ago

        The point of this exercise is to say “ha-ha gotcha, I’m so clever neener neener” while everyone else rolls their eyes.

        • Angry_Autist (he/him)@lemmy.world
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          7 hours ago

          Science is only one facet of life where definitions are important, and arguably not even the most daily impactful.

          Also science is one of the few arenas with any real interest in a rigorous epistemic framework so that same concept of advancing definitions doesn’t work with social values, political situations, and most media where definitions are changed or co-opted for convenience and leverage rather than objective rhetorical value.

          Pretending they do leads to things like ‘we will become more progressive over time as a society’ being accepted as truisms of human nature instead of the long-term efforts of hundreds of thousands of highly motivated and violently targeted individuals working to better the world for people they will never meet.

          So yes, rigorous definitions in science is important, and thankfully we have developed many useful frameworks to ensure that no matter where in the world scientists share knowledge that it can be held to certain standards of rigor and objectivity

          Literally no other facet of life has that same kind of special protection.

  • Angry_Autist (he/him)@lemmy.world
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    8 hours ago

    It wasn’t funny when Diogenes did it and it isn’t funny now but it keeps getting reposted anyway and we have to pretend it is

    • logicbomb@lemmy.world
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      9 hours ago

      Yeah, that pretty much sums it up. Wikipedia calls a square a “regular quadrilateral,” which seems like a decent enough definition.

      Today I learned that when you make up your own inadequate definition, then it’s easy to match the definition with something inadequate.