Historically Speaking,—: Johan de Witt's kinematical constructions of the conics

1963 ◽  
Vol 56 (8) ◽  
pp. 632-635
Author(s):  
Joy B. Easton

In second-year algebra courses the conic sections are defined as type-quadratic equations and the graphs of the curves plotted. It is difficult at this level to relate these equations to the usual geometric definitions of the curves. There arc, however, a number of little-known locus definitions which lead immediately to the canonical equations through the application of elementary theorems of proportion which should be familiar to students of plane geometry.

1955 ◽  
Vol 48 (1) ◽  
pp. 42-44
Author(s):  
Ethel Saupe

In second year algebra courses students are normally introduced to the conic sections by being told that certain curves which may be represented by quadratic equations in two unknowns are, in fact, equations of conic sections. In solid geometry the same students are told that a section of a right circular cone made by a plane is a conic section. Various kinds of models are occasionally employed to illustrate what the conic sections look like in the geometric sense, but ordinarily little effort is made to tie up the fact that a relation exists between the introduction given in algebra and the models presented in solid geometry.


2019 ◽  
Vol 112 (4) ◽  
pp. 312-316
Author(s):  
Wayne Nirode

One of my goals, as a geometry teacher, is for my students to develop a deep and flexible understanding of the written definition of a geometric object and the corresponding prototypical diagram. Providing students with opportunities to explore analogous problems is an ideal way to help foster this understanding. Two ways to do this is either to change the surface from a plane to a sphere or change the metric from Pythagorean distance to taxicab distance (where distance is defined as the sum of the horizontal and vertical components between two points). Using a different surface or metric can have dramatic effects on the appearance of geometric objects. For example, in spherical geometry, triangles that are impossible in plane geometry (such as triangles with three right or three obtuse angles) are now possible. In taxicab geometry, a circle now looks like a Euclidean square that has been rotated 45 degrees.


1922 ◽  
Vol 15 (7) ◽  
pp. 381-391
Author(s):  
William David Reeve

I shall not attempt, in this paper, to discredit our traditional methods of teaching algebra in the first year of the high school, followed by plane geometry in the second year, intermediate algebra in the third year, and so on. I say this in spite of the fact that much of our traditional practice and the accompanying results might justify one in so doing. In short, I am not interested in a destructive type of criticism of past methods with a view to setting up new bits of content (or at least reorganized content) and technique of procedure. Certainly, I should not favor a method which would seem to be attempting to force any set program upon the teaching body. The best progress is not made in that way. With many teachers of mathematics, the traditional order of treatment, if not the traditional methods, will prevail. Moreover, this will he true even after much experience and available scientific data may make a trial of some form of reorganized content and methods seem wise and feasible.


1773 ◽  
Vol 63 ◽  
pp. 340-360

Sir, You well know that the curves formed by the sections of a cone, and therefore called Conic Sections, have, from the earliest ages of geometry, engaged the attention of mathematicians, on account of their extensive utility in the solution of many problems, which were incapable of being constructed by an possible combination of right lines and circles, the magnitudes used in plane geometry.


1945 ◽  
Vol 38 (3) ◽  
pp. 120-125
Author(s):  
William A. Cordrey

The advent of quadratic equations antedates the dawn of the Christian era by about two millennia. The study of conics, however, did not get under way until the fourth century prior to the birth of Christ. The first writer on this subject, Menaechmus, used the parabola and hyperbola in duplicating the cube. Several years later Euclid wrote a treatise on conic sections. This work was continued by Apollonius, whose investigations added much to the existing knowdedge of the subject.


1964 ◽  
Vol 57 (6) ◽  
pp. 415-416
Author(s):  
Henry D. Snyder

In a study of quadratic equations and quadratic functions, my second-year algebra class embarked on a discovery lesson which turned out to be the most successful class session I have ever had. The lesson plan called for a consideration of quadratic inequalities and their solutions, but we began as usual by discussing the homework of the previous day.


2019 ◽  
Vol 112 (5) ◽  
pp. 330-337
Author(s):  
Elaine M. Purvinis ◽  
Joshua B. Fagan

In first- and second-year algebra classrooms, the all-too-familiar whine of “when are we ever going to use this in real life?” challenges mathematics teachers to find new, engaging ways to present mathematical concepts. The introduction of quadratic equations is typically modeled by describing the motion of a moving object with respect to time, and typical lessons include uninspiring textbook practice problems that portray dropping or shooting objects from given distances or at particular time intervals. For a novel approach to exploring quadratics, we chose to step outside the classroom to look at some phenomena in the field of acoustics. Our activity incorporates mathematical modeling to provide a multirepresentational view of the math behind the physics and to provide a conceptual basis for analyzing and understanding a real-world quadratic situation.


2007 ◽  
Vol 38 (6) ◽  
pp. 80
Author(s):  
MARY ELLEN SCHNEIDER
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