`The cos (expr)` function returns the cosine of the expression `expr`, where `expr` is expressed in radians. The following code block shows an example of a cosine function:

$ vi cosfunc.awkBEGIN {print "cos(90) = ", cos(90);print "cos(45) = ", cos(45);}$ awk -f cosfunc.awk

The output of the execution of the previous code is as follows:

cos(90) = -0.448074cos(45) = 0.525322

The remaining trigonometric functions, such as `sec()`, `cosec()`, `tan()`, and `cot()`, are measured in radians, and can be obtained with the use of the `sin()` and `cos()` functions.