Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: POWERS,SERIES,SIMPLY,BY COMPASS AND RULER.
Replies: 1   Last Post: Aug 15, 2005 2:11 PM

 Messages: [ Previous | Next ]
 Eur Ing Panagiotis Stefanides Posts: 567 Registered: 12/3/04
POWERS,SERIES,SIMPLY,BY COMPASS AND RULER.
Posted: Aug 10, 2005 12:11 PM

Powers of a Length A[ab] Graphically by Compass and Ruler.
[The theory simply lies on the "similar orthogonal triangles"]

Draw a line horizontally of the Unit length of the Ruler.
Let it be [ej] ,and A avertical line [jh] ,at j corresponding to the Length A ,picked up by the compass.
Then [ej] will be the hypotenuse of the orthogonal triangle [ejh].
Let THETA be the angle whose tangent is: [hj]/[ej]=A/1=A.
We extend the line [ej] to [k],and [eh] to [q].
We use the compass and place the length A on [ek] ,
so we get a point on it [m] , that [em]=A.
Then , we draw a vertical line on [em] at [m],which meets
the line [eq] at [n].
Then [mn]=[A^2] , and tanTHETA= A.
So we have graphically obtained the square of the Length A , GRAPHICALLY BY COMPASS and RULER .
We pick up the length [A^2] lay it along line [ek] so
we get a point on it [r] ,so that [er]=A^2 , the vertical
on it ,meets [eq] at [s] ,so [rs]=A^3, and tanTHETA=A.
By doing so we get the powers we need of a length graphically by compass and ruler.
So any series that involves powers of a length x
[ such as e^x=1+x+[1/2!]x^2+... , log x , trigs etc ], may be drawn graphically.
Of course a similar method is involved for the product
of two lengths , inverses ,etc.
[The inverse 1/A is obtained
from the original triangle taking as vertical the Unit Length of the ruler.
Then the horizontal length is 1/A and tanTHETA=A]
Copyright 2005 Eur Ing Panagiotis Stefanides

Regards from Athens,

Panagiotis Stefanides
http://www.stefanides.gr

Date Subject Author
8/10/05 Eur Ing Panagiotis Stefanides
8/15/05 Eur Ing Panagiotis Stefanides