conchoid

conchoid englanniksi

1. Any of a family of curves defined as the locus of points ''p'', such that each ''p'' is on a line that passes through a given fixed point ''P'' and intersects a given curve, ''C'', and the distance from ''p'' to the point of intersection with ''C'' is a specified constant (note that for nontrivial cases two such points ''p'' satisfy the criteria, and the resultant curve has two parts). (C)

''The conchoid of a circle with respect to a point on the circle is a cardioid if the fixed distance is equal to the diameter of the circle.''

''The Conchoid of Nicomedes is the conchoid of a straight line with respect to a point not on the line.''

2. 1815, Charles Hutton, ''of Alexandria|Pappus'', entry in ''A Philosophical and Mathematical Dictionary'', Volume 2, page 147,

He next treats of the properties of the Conchoid, which Nicomedes invented for doubling the cube; applying it to the solution of certain problems concerning Inclinations, with the finding of two mean proportionals, and cubes in any proportion whatever.

3. (quote-text)

4. A conchoidal fracture in rock.

5. {{quote-journal|en|year=1948|author=Tennessee Valley Authority|title=The Hiwassee Valley Projects|journal=Technical Report|issue=5|volume=2|pageurl=http://books.google.com.au/books?id=gcs_AQAAIAAJ&q=%22conchoids%22&dq=%22conchoids%22&hl=en&sa=X&ei=CVipU6X2IojRkwWe_4CgBQ&redir_esc=y|page=359