\[\cos \left(x + \varepsilon\right) - \cos x\]
Test:
NMSE problem 3.3.5
Bits:
128 bits
Bits error versus x
Bits error versus eps
Time: 25.5 s
Input Error: 39.4
Output Error: 24.7
Log:
Profile: 🕒
\(\frac{(\left(-\sin \varepsilon\right) * \left(\sin x\right) + \left(\cos x \cdot \cos \varepsilon\right))_* - \cos x}{\frac{(\left(\cos x\right) * \left(\cos \varepsilon\right) + \left(\cos x\right))_* - \left(-\sin x \cdot \sin \varepsilon\right)}{(\left(\cos x\right) * \left(\cos \varepsilon\right) + \left(\cos x\right))_* - \left(-\sin x \cdot \sin \varepsilon\right)}}\)
  1. Started with
    \[\cos \left(x + \varepsilon\right) - \cos x\]
    39.4
  2. Using strategy rm
    39.4
  3. Applied cos-sum to get
    \[\color{red}{\cos \left(x + \varepsilon\right)} - \cos x \leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x\]
    24.7
  4. Using strategy rm
    24.7
  5. Applied sub-neg to get
    \[\color{red}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x \cdot \sin \varepsilon\right)\right)} - \cos x\]
    24.7
  6. Applied associate--l+ to get
    \[\color{red}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x \cdot \sin \varepsilon\right)\right) - \cos x} \leadsto \color{blue}{\cos x \cdot \cos \varepsilon + \left(\left(-\sin x \cdot \sin \varepsilon\right) - \cos x\right)}\]
    24.7
  7. Using strategy rm
    24.7
  8. Applied flip-+ to get
    \[\color{red}{\cos x \cdot \cos \varepsilon + \left(\left(-\sin x \cdot \sin \varepsilon\right) - \cos x\right)} \leadsto \color{blue}{\frac{{\left(\cos x \cdot \cos \varepsilon\right)}^2 - {\left(\left(-\sin x \cdot \sin \varepsilon\right) - \cos x\right)}^2}{\cos x \cdot \cos \varepsilon - \left(\left(-\sin x \cdot \sin \varepsilon\right) - \cos x\right)}}\]
    24.9
  9. Applied simplify to get
    \[\frac{{\left(\cos x \cdot \cos \varepsilon\right)}^2 - {\left(\left(-\sin x \cdot \sin \varepsilon\right) - \cos x\right)}^2}{\color{red}{\cos x \cdot \cos \varepsilon - \left(\left(-\sin x \cdot \sin \varepsilon\right) - \cos x\right)}} \leadsto \frac{{\left(\cos x \cdot \cos \varepsilon\right)}^2 - {\left(\left(-\sin x \cdot \sin \varepsilon\right) - \cos x\right)}^2}{\color{blue}{(\left(\cos \varepsilon\right) * \left(\cos x\right) + \left(\cos x\right))_* - \sin x \cdot \left(-\sin \varepsilon\right)}}\]
    25.0
  10. Applied taylor to get
    \[\frac{{\left(\cos x \cdot \cos \varepsilon\right)}^2 - {\left(\left(-\sin x \cdot \sin \varepsilon\right) - \cos x\right)}^2}{(\left(\cos \varepsilon\right) * \left(\cos x\right) + \left(\cos x\right))_* - \sin x \cdot \left(-\sin \varepsilon\right)} \leadsto \frac{{\left(\cos x \cdot \cos \varepsilon\right)}^2 - {\left(\left(-\sin x \cdot \sin \varepsilon\right) - \cos x\right)}^2}{(\left(\cos \varepsilon\right) * \left(\cos x\right) + \left(\cos x\right))_* - \sin x \cdot \left(-\sin \varepsilon\right)}\]
    25.0
  11. Taylor expanded around 0 to get
    \[\frac{{\left(\cos x \cdot \cos \varepsilon\right)}^2 - {\left(\left(-\sin x \cdot \sin \varepsilon\right) - \cos x\right)}^2}{\color{red}{(\left(\cos \varepsilon\right) * \left(\cos x\right) + \left(\cos x\right))_*} - \sin x \cdot \left(-\sin \varepsilon\right)} \leadsto \frac{{\left(\cos x \cdot \cos \varepsilon\right)}^2 - {\left(\left(-\sin x \cdot \sin \varepsilon\right) - \cos x\right)}^2}{\color{blue}{(\left(\cos \varepsilon\right) * \left(\cos x\right) + \left(\cos x\right))_*} - \sin x \cdot \left(-\sin \varepsilon\right)}\]
    25.0
  12. Applied simplify to get
    \[\frac{{\left(\cos x \cdot \cos \varepsilon\right)}^2 - {\left(\left(-\sin x \cdot \sin \varepsilon\right) - \cos x\right)}^2}{(\left(\cos \varepsilon\right) * \left(\cos x\right) + \left(\cos x\right))_* - \sin x \cdot \left(-\sin \varepsilon\right)} \leadsto \frac{\sin \varepsilon \cdot \left(-\sin x\right) - \left(\cos x - \cos \varepsilon \cdot \cos x\right)}{(\left(\cos \varepsilon\right) * \left(\cos x\right) + \left(\cos x\right))_* - \sin \varepsilon \cdot \left(-\sin x\right)} \cdot \left(\cos \varepsilon \cdot \cos x - \left(\sin \varepsilon \cdot \left(-\sin x\right) - \cos x\right)\right)\]
    6.7

  13. Applied final simplification
  14. Applied simplify to get
    \[\color{red}{\frac{\sin \varepsilon \cdot \left(-\sin x\right) - \left(\cos x - \cos \varepsilon \cdot \cos x\right)}{(\left(\cos \varepsilon\right) * \left(\cos x\right) + \left(\cos x\right))_* - \sin \varepsilon \cdot \left(-\sin x\right)} \cdot \left(\cos \varepsilon \cdot \cos x - \left(\sin \varepsilon \cdot \left(-\sin x\right) - \cos x\right)\right)} \leadsto \color{blue}{\frac{(\left(-\sin \varepsilon\right) * \left(\sin x\right) + \left(\cos x \cdot \cos \varepsilon\right))_* - \cos x}{\frac{(\left(\cos x\right) * \left(\cos \varepsilon\right) + \left(\cos x\right))_* - \left(-\sin x \cdot \sin \varepsilon\right)}{(\left(\cos x\right) * \left(\cos \varepsilon\right) + \left(\cos x\right))_* - \left(-\sin x \cdot \sin \varepsilon\right)}}}\]
    24.7

Original test:


(lambda ((x default) (eps default))
  #:name "NMSE problem 3.3.5"
  (- (cos (+ x eps)) (cos x)))