The use of trigonometry in making astronomical calculations prior to the invention of logarithms is discussed. (JT)

A class of triangles related to the Pythagorean triangles is described; theorems concerning this class are proved. (SD)

Computer graphics are used to display the sum of the first few terms of the series solution for the problem of the vibrating string frequently discussed in introductory courses on differential equations. (MNS)

An old way to determine asymptotes for curves described in polar coordinates is presented. Practice in solving trigonometric equations, in differentiation, and in calculating limits is involved. (MNS)

How to determine when there is a unique solution when two sides and an angle of a triangle are known, using simple algebra and the law of cosines, is described. (MNS)

The author argues that sine, secant, and tangent should be taught as the three basic trigonometric functions rather than sine, cosine, and tangent. (SD)

How does your calculator quickly produce values of trigonometric functions? You might be surprised to learn that it does not use series or polynomial approximations, but rather the so-called CORDIC method. This paper will focus on the geometry of the CORDIC method, as originally developed by Volder in 1959. This algorithm is a wonderful…

Techniques which use the shadow of the earth as a reference in relation to the angular radii of the sun and moon permit determination of the distance from the earth to the moon. (TS)

Presented are some of the special properties possessed by a triangle in which the measure of one of its three angles is one-half the measure of another of these angles. The author names such a triangle a vux triangle. (RP)

Describes the college-level course offered at the State University of New York, which combines plane geometry and plane trigonometry. Explains lesson sequences and sample exercises to show how the course develops all of the major principles of geometry and trigonometry using three basic constructions: perpendicularity, angle congruency, and angle…

A process for eliminating the xy term in a quadratic equation in two variables is presented. The author feels this process will be within the reach of more high school students than more commonly used methods. (MK)

Derivations of elementary trigonometric identities involving constants (namely, particular values of the sine function) are presented. (MK)