Average Error: 0.5 → 0.4
Time: 6.7s
Precision: 64
\[\sqrt{x - 1} \cdot \sqrt{x}\]
↓
\[\left(x - 0.5\right) - \frac{0.125}{x}\]
\sqrt{x - 1} \cdot \sqrt{x}
↓
\left(x - 0.5\right) - \frac{0.125}{x}
double f(double x) {
        double r3697 = x;
        double r3698 = 1.0;
        double r3699 = r3697 - r3698;
        double r3700 = sqrt(r3699);
        double r3701 = sqrt(r3697);
        double r3702 = r3700 * r3701;
        return r3702;
}
↓
double f(double x) {
        double r3703 = x;
        double r3704 = 0.5;
        double r3705 = r3703 - r3704;
        double r3706 = 0.125;
        double r3707 = r3706 / r3703;
        double r3708 = r3705 - r3707;
        return r3708;
}

Error

Bits error versus x

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Derivation

  1. Initial program 0.5

    \[\sqrt{x - 1} \cdot \sqrt{x}\]

  2. Taylor expanded around inf 0.4

    \[\leadsto \color{blue}{x - \left(0.5 + 0.125 \cdot \frac{1}{x}\right)}\]

  3. Simplified0.4

    \[\leadsto \color{blue}{\left(x - 0.5\right) - \frac{0.125}{x}}\]

  4. Final simplification0.4

    \[\leadsto \left(x - 0.5\right) - \frac{0.125}{x}\]

Reproduce

herbie shell --seed 2019351 +o rules:numerics
(FPCore (x)
  :name "sqrt times"
  :precision binary64
  (* (sqrt (- x 1)) (sqrt x)))