Function frexp 

pub fn frexp(x: f64) -> (f64, i32)

Split x into a mantissa m in [0.5, 1) (sign preserved) and an integer exponent e such that x == m * 2^e.

Zero, infinities and NaN return (x, 0).

use mathverse_core::float::frexp;
let (m, e) = frexp(6.0);
assert_eq!(m, 0.75);
assert_eq!(e, 3);