Have you thought of using `sqrt()` instead of `powf()`? I think it would be more clear to use the first. Additionaly, you don't actually need to cast `i` to `f64`. If you use `range_inclusive(1.0, 100.0)` then `i` will be `f64`.

Also, I think you should add `use std::iter::range_inclusive`, since you use it two times and it is what you would do in a real program.