#### 1.3.2 Evaluation Notation

In the examples in this manual, results from expressions that you evaluate are indicated with ‘`⇒`’. For example:

    sqrt (2)
         ⇒ 1.4142

You can read this as “`sqrt (2)` evaluates to 1.4142”.

In some cases, matrix values that are returned by expressions are displayed like this

    [1, 2; 3, 4] == [1, 3; 2, 4]
         ⇒ [ 1, 0; 0, 1 ]

and in other cases, they are displayed like this

    eye (3)
         ⇒  1  0  0
             0  1  0
             0  0  1

in order to clearly show the structure of the result.

Sometimes to help describe one expression, another expression is shown that produces identical results. The exact equivalence of expressions is indicated with ‘`≡`’. For example:

    rot90 ([1, 2; 3, 4], -1)
    ≡
    rot90 ([1, 2; 3, 4], 3)
    ≡
    rot90 ([1, 2; 3, 4], 7)