Ржавкий квадратный корень

/// Options:
//  -> call the `sqrt()` function
//  -> call the `powf()` function with 1/2 or 0.5
//  
/// Example:
fn main() {
    let x = 2f32;               //  or f64
    let sqrt = &x.sqrt();       //  call sqrt()
    let sqrt2 = &x.powf(0.5);   //  call powf()
}
/// Note:
//  The second option can also be applied to other
//  roots. For the nth root it is then powf(1/n).
SnefDen