In its more basic sense, trigonometry is the study of the relationships between the sides and the angles of [[triangle]]s. However, trigonometric functions are widely used outside their original realm of describing triangles. For example, sinusoidal functions (sine and cosine) are used to describe oscillatory motion and waves. In fact, there are extremely deep and fruitful connections among those functions, the exponential function, complex numbers, [[Fourier transform|Fourier]] and Laplace transforms, and signal processing. | In its more basic sense, trigonometry is the study of the relationships between the sides and the angles of [[triangle]]s. However, trigonometric functions are widely used outside their original realm of describing triangles. For example, sinusoidal functions (sine and cosine) are used to describe oscillatory motion and waves. In fact, there are extremely deep and fruitful connections among those functions, the exponential function, complex numbers, [[Fourier transform|Fourier]] and Laplace transforms, and signal processing. |