# Definition of trigonometric function in US English:

## trigonometric function

### noun

Mathematics
• A function of an angle, or of an abstract quantity, used in trigonometry, including the sine, cosine, tangent, cotangent, secant, and cosecant, and their hyperbolic counterparts.

Also called circular function
• ‘As Eisenstein shows, his method for constructing elliptic functions applies beautifully to the simpler case of trigonometric functions.’
• ‘Napier also found exponential expressions for trigonometric functions, and introduced the decimal notation for fractions.’
• ‘It was also in Berlin that he discovered the famous Euler's Identity giving the value of the exponential function in terms of the trigonometric functions sine and cosine.’
• ‘It handles general math functions, exponential and logarithmic functions, and trigonometric functions.’
• ‘Special functions, which include the trigonometric functions, might be called ‘useful ‘functions.’’
• ‘The necessary background mathematical tools are then introduced such as the arithmetical operations on sexagesimal fractions and the trigonometric functions.’
• ‘Some readers raised on an analytic treatment, with its abundance of hyperbolic trigonometric functions, natural logarithms and the like, may find the synthetic approach, using only Euclidean circles and lines, somewhat surprising.’
• ‘Many of the Arabic mathematicians produced tables of trigonometric functions as part of their studies of astronomy.’
• ‘Vega wrote on artillery but he is best remembered for his tables of logarithms and trigonometric functions.’
• ‘The tables of logarithms which he published included logarithms of trigonometric functions for use by astronomers.’