You can use local variables inside `check all`

block by entering `var`

keyword.

There are important restrictions on the use of variables. First, you cannot change their value after it has been calculated. Secondly, each time the predicate is called, the value of a local variable is calculated only once. That is, if you use the variable reference several times within the predicate, the value will be calculated only when you first use

```
# Testing for sin & cos
def test() means
check all
var angle = 35
var cosinus = Math.cos(angle)
var sinus = Math.sin(angle)
var sum of squares = Math.pow(cosinus, 2) + Math.pow(sinus, 2)
# considering the features of the library java.lang.Math
# and inaccurate calculations when converting degrees to radians
sum of squares <= 1
sum of squares >= 0.999999
end
end def
```