# MathFun: Miscellaneous Mathematical Functions

### Description

`abs(x)` computes the absolute value of x, `sqrt(x)` computes the (principal) square root of x, √{x}.

The naming follows the standard for computer languages such as C or Fortran.

### Usage

 ```1 2``` ```abs(x) sqrt(x) ```

### Arguments

 `x` a numeric or `complex` vector or array.

### Details

These are internal generic primitive functions: methods can be defined for them individually or via the `Math` group generic. For complex arguments (and the default method), `z`, ```abs(z) == Mod(z)``` and `sqrt(z) == z^0.5`.

`abs(x)` returns an `integer` vector when `x` is `integer` or `logical`.

### S4 methods

Both are S4 generic and members of the `Math` group generic.

### References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

`Arithmetic` for simple, `log` for logarithmic, `sin` for trigonometric, and `Special` for special mathematical functions.

‘plotmath’ for the use of `sqrt` in plot annotation.

### Examples

 ```1 2 3 4 5``` ```require(stats) # for spline require(graphics) xx <- -9:9 plot(xx, sqrt(abs(xx)), col = "red") lines(spline(xx, sqrt(abs(xx)), n=101), col = "pink") ```

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