1 | initial version |

When you write `var('i')`

, you define `i`

as a symbol. In particular, `2*i`

is an element of the symbolic ring, not the rationals, but you ask that `2*i`

be an entry of a matrix whose coefficients are rationals (because of the `QQ`

at the beginnig).

If you want the imaginary number, you should use the already defined `I`

, if you want a matrix over, say the algabraic numbers (so that `I`

in an element), you should write:

```
sage: matrix(QQbar,2,2,[[2*I,-2],[3,4]])
[2*I -2]
[ 3 4]
```

2 | No.2 Revision |

When you write `var('i')`

, you define `i`

as a symbol. In particular, `2*i`

is an element of the symbolic ring, not the rationals, but you ask that `2*i`

be an entry of a matrix whose coefficients are rationals (because of the `QQ`

at the beginnig).

If you want the imaginary number, you should use the already defined `I`

, if you want a matrix over, say the algabraic numbers `QQbar`

(so that `I`

in an element), you should write:

```
sage: matrix(QQbar,2,2,[[2*I,-2],[3,4]])
[2*I -2]
[ 3 4]
```

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