\[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1}\]
Test:
NMSE problem 3.3.3
Bits:
128 bits
Bits error versus x
Time: 22.1 s
Input Error: 4.0
Output Error: 8.1
Log:
Profile: 🕒
\(\frac{\frac{4 - (\left(x \cdot 4\right) * x + \left(x \cdot 4\right))_*}{{\left((x * x + x)_*\right)}^2 \cdot {\left(x - 1\right)}^2}}{\left(\frac{1}{1 + x} - \frac{2}{x}\right) - \frac{1}{x - 1}}\)
  1. Started with
    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1}\]
    4.0
  2. Using strategy rm
    4.0
  3. Applied flip-+ to get
    \[\color{red}{\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1}} \leadsto \color{blue}{\frac{{\left(\frac{1}{x + 1} - \frac{2}{x}\right)}^2 - {\left(\frac{1}{x - 1}\right)}^2}{\left(\frac{1}{x + 1} - \frac{2}{x}\right) - \frac{1}{x - 1}}}\]
    11.3
  4. Using strategy rm
    11.3
  5. Applied square-div to get
    \[\frac{{\left(\frac{1}{x + 1} - \frac{2}{x}\right)}^2 - \color{red}{{\left(\frac{1}{x - 1}\right)}^2}}{\left(\frac{1}{x + 1} - \frac{2}{x}\right) - \frac{1}{x - 1}} \leadsto \frac{{\left(\frac{1}{x + 1} - \frac{2}{x}\right)}^2 - \color{blue}{\frac{{1}^2}{{\left(x - 1\right)}^2}}}{\left(\frac{1}{x + 1} - \frac{2}{x}\right) - \frac{1}{x - 1}}\]
    13.6
  6. Applied frac-sub to get
    \[\frac{{\color{red}{\left(\frac{1}{x + 1} - \frac{2}{x}\right)}}^2 - \frac{{1}^2}{{\left(x - 1\right)}^2}}{\left(\frac{1}{x + 1} - \frac{2}{x}\right) - \frac{1}{x - 1}} \leadsto \frac{{\color{blue}{\left(\frac{1 \cdot x - \left(x + 1\right) \cdot 2}{\left(x + 1\right) \cdot x}\right)}}^2 - \frac{{1}^2}{{\left(x - 1\right)}^2}}{\left(\frac{1}{x + 1} - \frac{2}{x}\right) - \frac{1}{x - 1}}\]
    12.6
  7. Applied square-div to get
    \[\frac{\color{red}{{\left(\frac{1 \cdot x - \left(x + 1\right) \cdot 2}{\left(x + 1\right) \cdot x}\right)}^2} - \frac{{1}^2}{{\left(x - 1\right)}^2}}{\left(\frac{1}{x + 1} - \frac{2}{x}\right) - \frac{1}{x - 1}} \leadsto \frac{\color{blue}{\frac{{\left(1 \cdot x - \left(x + 1\right) \cdot 2\right)}^2}{{\left(\left(x + 1\right) \cdot x\right)}^2}} - \frac{{1}^2}{{\left(x - 1\right)}^2}}{\left(\frac{1}{x + 1} - \frac{2}{x}\right) - \frac{1}{x - 1}}\]
    21.2
  8. Applied frac-sub to get
    \[\frac{\color{red}{\frac{{\left(1 \cdot x - \left(x + 1\right) \cdot 2\right)}^2}{{\left(\left(x + 1\right) \cdot x\right)}^2} - \frac{{1}^2}{{\left(x - 1\right)}^2}}}{\left(\frac{1}{x + 1} - \frac{2}{x}\right) - \frac{1}{x - 1}} \leadsto \frac{\color{blue}{\frac{{\left(1 \cdot x - \left(x + 1\right) \cdot 2\right)}^2 \cdot {\left(x - 1\right)}^2 - {\left(\left(x + 1\right) \cdot x\right)}^2 \cdot {1}^2}{{\left(\left(x + 1\right) \cdot x\right)}^2 \cdot {\left(x - 1\right)}^2}}}{\left(\frac{1}{x + 1} - \frac{2}{x}\right) - \frac{1}{x - 1}}\]
    21.5
  9. Applied taylor to get
    \[\frac{\frac{{\left(1 \cdot x - \left(x + 1\right) \cdot 2\right)}^2 \cdot {\left(x - 1\right)}^2 - {\left(\left(x + 1\right) \cdot x\right)}^2 \cdot {1}^2}{{\left(\left(x + 1\right) \cdot x\right)}^2 \cdot {\left(x - 1\right)}^2}}{\left(\frac{1}{x + 1} - \frac{2}{x}\right) - \frac{1}{x - 1}} \leadsto \frac{\frac{4 - \left(4 \cdot {x}^2 + 4 \cdot x\right)}{{\left(\left(x + 1\right) \cdot x\right)}^2 \cdot {\left(x - 1\right)}^2}}{\left(\frac{1}{x + 1} - \frac{2}{x}\right) - \frac{1}{x - 1}}\]
    17.7
  10. Taylor expanded around 0 to get
    \[\frac{\frac{\color{red}{4 - \left(4 \cdot {x}^2 + 4 \cdot x\right)}}{{\left(\left(x + 1\right) \cdot x\right)}^2 \cdot {\left(x - 1\right)}^2}}{\left(\frac{1}{x + 1} - \frac{2}{x}\right) - \frac{1}{x - 1}} \leadsto \frac{\frac{\color{blue}{4 - \left(4 \cdot {x}^2 + 4 \cdot x\right)}}{{\left(\left(x + 1\right) \cdot x\right)}^2 \cdot {\left(x - 1\right)}^2}}{\left(\frac{1}{x + 1} - \frac{2}{x}\right) - \frac{1}{x - 1}}\]
    17.7
  11. Applied simplify to get
    \[\frac{\frac{4 - \left(4 \cdot {x}^2 + 4 \cdot x\right)}{{\left(\left(x + 1\right) \cdot x\right)}^2 \cdot {\left(x - 1\right)}^2}}{\left(\frac{1}{x + 1} - \frac{2}{x}\right) - \frac{1}{x - 1}} \leadsto \frac{\frac{4 - (\left(x \cdot 4\right) * x + \left(x \cdot 4\right))_*}{{\left((x * x + x)_*\right)}^2 \cdot {\left(x - 1\right)}^2}}{\left(\frac{1}{1 + x} - \frac{2}{x}\right) - \frac{1}{x - 1}}\]
    8.1

  12. Applied final simplification

Original test:


(lambda ((x default))
  #:name "NMSE problem 3.3.3"
  (+ (- (/ 1 (+ x 1)) (/ 2 x)) (/ 1 (- x 1)))
  #:target
  (/ 2 (* x (- (sqr x) 1))))