\[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\]

↓

\[\frac{\frac{1}{a} - \frac{1}{b}}{b - a} \cdot \frac{1}{\frac{a + b}{\frac{\pi}{2}}}\]

Derivation

Initial program 14.2
\[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\]
Initial simplification0.3
\[\leadsto \frac{\frac{1}{a} - \frac{1}{b}}{b - a} \cdot \frac{\frac{\pi}{2}}{a + b}\]
Using strategy rm
Applied *-un-lft-identity0.3
\[\leadsto \frac{\frac{1}{a} - \frac{1}{b}}{b - a} \cdot \frac{\color{blue}{1 \cdot \frac{\pi}{2}}}{a + b}\]
Applied associate-/l*0.3
\[\leadsto \frac{\frac{1}{a} - \frac{1}{b}}{b - a} \cdot \color{blue}{\frac{1}{\frac{a + b}{\frac{\pi}{2}}}}\]
Final simplification0.3
\[\leadsto \frac{\frac{1}{a} - \frac{1}{b}}{b - a} \cdot \frac{1}{\frac{a + b}{\frac{\pi}{2}}}\]

Runtime

	Baseline	Herbie	Oracle	Span	%
Regimes	0.3	0.3	0.0	0.3	0%

herbie shell --seed 2018295 
(FPCore (a b)
  :name "NMSE Section 6.1 mentioned, B"
  (* (* (/ PI 2) (/ 1 (- (* b b) (* a a)))) (- (/ 1 a) (/ 1 b))))

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