`abs(x)`

computes the absolute value of x, `sqrt(x)`

computes the
(principal) square root of x, \(\sqrt{x}\).

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

```
abs(x)
sqrt(x)
```

x

a numeric or `complex`

vector or array.

Both are S4 generic and members of the
`Math`

group generic.

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`

.

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.

# NOT RUN { 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") # }