by Guest » Mon Dec 27, 2021 3:14 pm
I don't speak that language so I don't know what he was saying, whether this was a joke or he was serious.
He appears to be talking about three "impossible constructions", "trisecting an arbitrary angle" (given an angle, using only the straight edge and compasses, divide it into three equal angles), "duplicating the cube" (given a cube, using only the three dimensional analogues of a straight edge and compasses, construct a cube with twice the volume), and "squaring the circle".
Each of those was proven to be impossible long ago using the concept of "constructable numbers". A number, x, is constructible if and only if, given a line segment of length 1, it is possible using only straight edge and compasses, to construct a line segment of length x. It has been proven that the only "constructible numbers" are those that are "algebraic of order a power of 2". For example, if we have a line segment of length 1, we can use compasses and straight edge to construct a perpendicular at one end of that segment, strike a length 1 on that perpendicular, then connect those two points constructing a line segment of length [tex]\sqrt{2}[/tex]. Of course, [tex]\sqrt{2}[/tex], is "algebraic of order 2" since it satisfies [tex]x^2= 2[/tex].
IF it were possible to trisect an arbitrary angle then it would be possible to construct a line segment satisfying a cubic equation- a number algebraic of order 3, NOT a power of two.
If it were possible to "duplicate the cube" taking, say, a cube of side length 1 so volume 1, we would have constructed a cube of volume 2, so side length [tex]\sqrt[3]{2}[/tex], a number algebraic of order 3, not a power of 2.
If it were possible to "square the circle", taking a circle of radius 1, so area [tex]\pi[/tex], you would construct a square of area [tex]\pi[/tex] so side length [tex]\sqrt{\pi}[/tex], a transcendental number, not algebraic of any order!