## Arithmetic Functions

Nine of the built-in functions can be classified as arithmetic functions. Most of them take a numeric argument and return a numeric value. Table 9.1 summarizes these arithmetic functions.

Table 9.1. awk’s Built-In Arithmetic Functions
 Awk Function Description cos(x) Returns cosine of x (x is in radians). exp(x) Returns e to the power x. int(x) Returns truncated value of x. log(x) Returns natural logarithm (base-e) of x. sin(x) Returns sine of x (x is in radians). sqrt(x) Returns square root of x. atan2(y,x) Returns arctangent of y/x in the range -π to π. rand( ) Returns pseudo-random number r, where 0 <= r < 1. srand(x) Establishes new seed for rand( ). If no seed is specified, uses time of day. Returns the old seed.

### Trigonometric Functions

The trigonometric functions cos( ) and sin( ) work the same way, taking a single argument that is the size of an angle in radians and returning the cosine or sine for that angle. (To convert from degrees to radians, multiply the number by π/180.) The trigonometric function atan2( ) takes two arguments and returns the arctangent of their quotient. The expression

`atan2(0, -1)`

produces π.

The function exp( ) uses the natural exponential, which is also known as base-e exponentiation. The expression

`exp(1)`

returns the natural number 2.71828, the base of the natural logarithms, referred to as e. Thus, exp(x) is e to the x-th power.

The log( ) function gives the inverse of the exp( ) function, the natural logarithm of x. The sqrt( ) function takes ...

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