\[\frac{\left(-b/2\right) - \sqrt{{b/2}^2 - a \cdot c}}{a}\]
Test:
NMSE problem 3.2.1
Bits:
128 bits
Bits error versus a
Bits error versus b/2
Bits error versus c
Time: 9.9 s
Input Error: 33.3
Output Error: 33.6
Log: ⚲
Profile: 🕒
\(\frac{-b/2}{a} - \frac{\sqrt{{b/2}^2 - a \cdot c}}{a}\)
  1. Started with
    \[\frac{\left(-b/2\right) - \sqrt{{b/2}^2 - a \cdot c}}{a}\]
    33.3
  2. Using strategy rm
    33.3
  3. Applied div-sub to get
    \[\color{red}{\frac{\left(-b/2\right) - \sqrt{{b/2}^2 - a \cdot c}}{a}} \leadsto \color{blue}{\frac{-b/2}{a} - \frac{\sqrt{{b/2}^2 - a \cdot c}}{a}}\]
    33.6

Original test:


(lambda ((a default) (b/2 default) (c default))
  #:name "NMSE problem 3.2.1"
  (/ (- (- b/2) (sqrt (- (sqr b/2) (* a c)))) a))