• wholookshere@lemmy.blahaj.zone
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            1 month ago

            Only true in Cartesian coordinates.

            A straight line in polar coordinates with the same tangent would be a circle.

            EDIT: it is still a “straight” line. But then the result of a square on a surface is not the same shape any more.

            • ltxrtquq@lemmy.ml
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              1 month ago

              A straight line in polar coordinates with the same tangent would be a circle.

              I’m not sure that’s true. In non-euclidean geometry it might be, but aren’t polar coordinates just an alternative way of expressing cartesian?

              Looking at a libre textbook, it seems to be showing that a tangent line in polar coordinates is still a straight line, not a circle.

              • wholookshere@lemmy.blahaj.zone
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                1 month ago

                I’m saying that the tangent of a straight line in Cartesian coordinates, projected into polar, does not have constant tangent. A line with a constant tangent in polar, would look like a circle in Cartesian.

                • ltxrtquq@lemmy.ml
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                  1 month ago

                  Polar Functions and dydx

                  We are interested in the lines tangent a given graph, regardless of whether that graph is produced by rectangular, parametric, or polar equations. In each of these contexts, the slope of the tangent line is dydx. Given r=f(θ), we are generally not concerned with r′=f′(θ); that describes how fast r changes with respect to θ. Instead, we will use x=f(θ)cosθ, y=f(θ)sinθ to compute dydx.

                  From the link above. I really don’t understand why you seem to think a tangent line in polar coordinates would be a circle.

  • RememberTheApollo_@lemmy.world
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    1 month ago

    Kinda forgot the sides being parallel part. Like missing a step in assembling IKEA furniture, its not gonna turn out right.

      • angrystego@lemmy.world
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        1 month ago

        This one is enclosed and contiguous though, the lines of the triangle end where the circular line starts. (The rest is just a drafting residue.)

        • finitebanjo@lemmy.world
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          1 month ago

          No, it is 2 contiguous regions. The line of separation is the bounding line of a “shape.”

          Otherwise, the entire whitespace outside of the region is also part of the shape, as is anything it touches.

            • finitebanjo@lemmy.world
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              1 month ago

              Well then the line of separation means nothing and then you’ve lost two right angles to the contiguous void.

                • finitebanjo@lemmy.world
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                  1 month ago

                  Without a distinction of where the cube begins or ends it does not because there is no cube and there are no angles.