Analytic definitions of the goniometric functions are presented that are close to heuristic geometrical situations. One can easily deduce the basis relations for the sine, cosine and tangent functions from the analytic definitions. Nevertheless, direct proofs for some of these relations, in particular the addition formulas, are given, using geometrical heuristics.
|Journal||International Journal of Mathematical Education in Science and Technology|
|Publication status||Published - 1997|