2.8 Calculating Trigonometric Functions

NN 2, IE 3

2.8.1 Problem

You want to invoke a variety of trigonometric functions, perhaps for calculating animation paths of a positioned element.

2.8.2 Solution

JavaScript's Math object comes with a typical complement of functions for trigonometric calculations. Each one requires one or two arguments and returns a result in radians. Arguments representing angles must also be expressed in radians. The following statement assigns the sine of a value to a variable:

var sineValue = Math.sin(radiansInput);

All Math object methods must be invoked as methods of the static Math object.

2.8.3 Discussion

See the introduction to this chapter for a summary of all Math object methods and constants. You can see an application of trigonometric functions in Recipe 13.10, which calculates the circular path for a positioned element to follow on the page.

2.8.4 See Also

Section 2.0.2 in the introduction of this chapter; Recipe 13.10 where some trigonometric operations help calculate points around a circular path.