Trigonometric identities are equations that describe relationships between the various trigonometric functions. The trigonometric functions are a set of functions that are employed in the study of angles and angular relationships in planar and...

In mathematics, trigonometric identities are equalities that involve trigonometric functions that are true for every single value of the occurring variables. These identities are useful whenever expressions involving trigonometric functions need to be...

INTRODUCTION The typical precalculus book contains the obscure trigonometric identities known as the product-to-sum formulas [1, p. 470 ]. They usually get short treatment (or none) in a precalculus course because they are so rarely used. This is unfortunate since they have an...

The Preble's meadow jumping mouse, once seen as a costly impediment to development, is now viewed by the government as a critter that never really existed -- and is no longer in need of federal protection under the Endangered Species Act. The Interior...