Saturday, 30 June 2012
Friday, 29 June 2012
Thursday, 28 June 2012
The Origin of the Word Quaternions
The following includes most of a note in the Analyst regarding Hamilton's meaning for the name Quaternions. It includes a poem it appears he wrote, which I had never seen.
Hope it is enjoyable to others.
ORIGIN OF THE NAME "QUATERNIONS".
BY PROF. W. W. JOHNSON, ANNAPOLIS, MD.
clipped from article:
It appears from the Preface to the "Lectures" (see page 47), that the four units are the heterogeneous quantities 1, i, j and k, of which the first is the real or scalar unit, and the others correspond to three
mutually rectangular directions in space. Hamilton had in fact found that expressing directed lines in the triplex form ix +jy + kz, x, y and z being real coefficients, he was able to interpret their product as of the form w+ix+jy+kz, a quadruplex quantity, viz.?the sum of a number and line, the latter being perpendicular to the plane of the factor lines.
It seems to have been a favorite conception of Hamilton's to refer the real quantities of simple Algebra to the uni-dimensional quantity time, as in his Essay on Algebra as the Science of Pure Time; thus in the combination of line and number to which his investigations led him, he saw united the one of time and the three of space, as expressed in the sonnet below, which was published after his death in an Article upon the life and genius of Hamilton, in the North British Review.
Sonnet by the Inventor of Quaternions.
(Supposed to have been addressed to Sir John Herschel.)
The Tetractys,
Or high Matheis, with her charm severe
Of line and number, was our theme; and we
Sought to behold her unborn progeny,
And thrones reserved in Truth's celestial sphere:
While views, before attained, became more clear;
And how the One of Time, of Space the Three,
Might, in the chain of Symbol, girdled be:
And when my eager and reverted ear
Caught some faint echoes of an ancient strain,
Some shadowy outlines of old thoughts sublime,
Gently he smiled to see, revived again,
In later age, and occidental clime,
A dimly traced Pythagorean lore,
A westward floating, mystic dream of four.
From "The Analyst Vol. 7, No. 2, Mar., 1880
Thony Christie sent the following comment shortly after I posted this :
William Wordsworth who was a good friend of Hamilton's when asked for his opinion on H's poetry told him he should stick to mathematics.
Wednesday, 27 June 2012
A Nice Old Geometry Problem
Recently, with thanks to the folks at JSTOR who have made many of the older issues of The American Mathematical Monthly available without subscription, I have been reading through some of the early issues.
This morning I came across two interesting circle problems that looked both interesting, and challenging to the typical High School student, so here they are. I will wait a couple of days and post the answers.
Enjoy,
18. Proposed by L. B. HAYWARD Superintendent of schools Bingham, Ohio:
In a circle whose radius is 6, find the area of the part between parallel chords
whose lengths are 8 and 10, both being on the same side of the center.
17. Proposed by H. W. HOLYCROSS, Superintendent of Schools, Pottersburg Union County, Ohio:
A gentleman owns a circular farm, and if three circles of equal area and as
large as possible be drawn within it, the circular area in the center of the farm will
contain one acre; what is the area of the circular farm ?
Solution 18
Solution 17
This morning I came across two interesting circle problems that looked both interesting, and challenging to the typical High School student, so here they are. I will wait a couple of days and post the answers.
Enjoy,
18. Proposed by L. B. HAYWARD Superintendent of schools Bingham, Ohio:
In a circle whose radius is 6, find the area of the part between parallel chords
whose lengths are 8 and 10, both being on the same side of the center.
17. Proposed by H. W. HOLYCROSS, Superintendent of Schools, Pottersburg Union County, Ohio:
A gentleman owns a circular farm, and if three circles of equal area and as
large as possible be drawn within it, the circular area in the center of the farm will
contain one acre; what is the area of the circular farm ?
Solution 18
Solution 17
Solution to Geom Problem 18
This is the solution to a problem posted here...
If you haven't tried the problem yet, don't read on below:
If you haven't tried the problem yet, don't read on below:
Solution to Geom Problem 17
This is a Solution to a geometry problem posted here. Don't read on if you haven't tried the problem:
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