 
 
 
6.6.1  Defining intervals
An interval is a range of real numbers, whose end points will be
floats with at least 15 significant digits. 
The i command creates intervals, with the arguments in square
brackets.
- 
i takes two arguments:
a and b, two real numbers.
- i[a,b] returns the interval between a and b.If a > b, then i[a,b] returns
i[evalf(b,15)-epsilon,evalf(a,15)+epsilon] (see
Section 2.5.7, item 2.5.7).
 
Intervals can also be created by following a decimal number with a
question mark. If the decimal number contains n digits, the
interval will be centered at a and have width 2· 10−n.
Examples
|  | | [1.00000000000000..1.18181818181819] |  |  |  |  |  |  |  |  |  |  | 
 | 
|  | | [1.73205080756886..3.14159265358980] |  |  |  |  |  |  |  |  |  |  | 
 | 
|  | | |  | ⎡ ⎣
 | 0.121999999999999..0.124000000000000 | ⎤ ⎦
 | 
 |  |  |  |  |  |  |  |  |  |  | 
 | 
|  | | |  | ⎡ ⎣
 | 0.789123454999990e3..0.789123456999998e3 | ⎤ ⎦
 | 
 |  |  |  |  |  |  |  |  |  |  | 
 | 
 
 
