  This paper is dedicated to providing an introduction into multidimensional
integer trigonometry. We start with an exposition of integer trigonometry in
two dimensions, which was introduced in 2008, and use this to generalise these
integer trigonometric functions to arbitrary dimension. We then move on to
study the basic properties of integer trigonometric functions. We find integer
trigonometric relations for transpose and adjacent simplicial cones, and for
the cones which generate the same simplices. Additionally, we discuss the
relationship between integer trigonometry, the Euclidean algorithm, and
continued fractions. Finally, we use adjacent and transpose cones to introduce
a notion of best approximations of simplicial cones. In two dimensions, this
notion of best approximation coincides with the classical notion of the best
approximations of real numbers.
