> For the complete documentation index, see [llms.txt](https://trizen.gitbook.io/sidef-lang/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://trizen.gitbook.io/sidef-lang/programming_tasks/r/roots_of_a_function.md).

# Roots of a function

```ruby
func f(x) {
    x*x*x - 3*x*x + 2*x
}
 
var step = 0.001
var start = -1
var stop = 3
 
for x in range(start+step, stop, step) {
    static sign = false
    given (var value = f(x)) {
        when (0) {
            say "Root found at #{x}"
        }
        case (sign && ((value > 0) != sign)) {
            say "Root found near #{x}"
        }
    }
    sign = value>0
}
```

#### Output:

```
Root found at 0
Root found at 1
Root found at 2
```