I have posted in the geometry research the following problem about angle trisection,but did not get a clear opinion ,and, since, here is a larger groub.
I will be glad to know if I wrote nonsense mathematics or something useful.here is the problem.
An arbitrary angle and its exact trisection angle fits exactly in the following symbolic triangle with the following sides:
a^3 , a*(b^2-a^2) , b*(b^2-2*a^2)
Where : 2 >= b/a >= sqrt(2)
(a,b):are positive real numbers
Of course, I have a hand written proofs for this fact.
Thanking you.
Bassam Karzeddin
Al Hussein Bin Talal University
JORDAN
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>
>
> An arbitrary angle and its exact trisection angle fits exactly in the following symbolic triangle with the following sides:
>
> a^3 , a*(b^2-a^2) , b*(b^2-2*a^2)
>
> Where : 2 >= b/a >= sqrt(2)
>
> (a,b):are positive real numbers
>
Solvetriangle in Macsyma tells us that there are
triangles with your specified sides and computes the
angles.
It is easy to confirm numerically that the second angle
is 3 times the first.
This appears to have no bearing on the impossibility of
trisecting an angle with ruler and compass, if that
is why you are interested in this.
See http://mathworld.wolfram.com/AngleTrisection.html
for related info.
[SIDES = [A^3,A*B^2-A^3,B^3-2*A^2*B],
ANGLES = [ACOS(B/(2*A)),
ACOS((B^3-3*A^2*B)/(2*A^3)),
%PI-ACOS((B^4-4*A^2*B^2+2*A^4)/(2*A^4))]]
Let s1, s2, s3 be the sides of the triangle, as you have defined them:
s1 := a^3
s2 := a*(b^2-a^2)
s3 := b*(b^2-2*a^2)
Let v1, v2, v3 be the angles opposite sides s1, s2, s3, respectively.
The from the law of cosines, we get:
s1^2 = s2^2 + s3^2 - 2*s2*s3*cos(v1)
whence:
cos(v1) = b/(2*a);
Similarly:
cos(v2) = b*(b^2 - 3*a^2)/(2*a^3)
cos(v3) = (4*a^2*b^2 - 2*a^4 - b^4)/(2*a^4)
Now apply the trigonometric identity:
cos(3*x) = 3*cos^3(x) - 3*cos(x)
to angle v1 and simplify:
cos(3*v1) = 3*cos^3(v1) - 3*cos(v1)
= 3*[ b/(2*a)]^3 - 3*[ b/(2*a)]
= b*(b^2 - 3*a^2)/(2*a^3).
Thus cos(3*v1) = cos(v2) which is cute. However I don't see a
relation between this and the classic angle trisection problem.
--
Rouben Rostamian