\[\cos \left(x + \varepsilon\right) - \cos x\]
Test:
NMSE problem 3.3.5
Bits:
128 bits
Bits error versus x
Bits error versus eps
Time: 22.5 s
Input Error: 40.2
Output Error: 0.5
Log:
Profile: 🕒
\(\begin{cases} \cos x \cdot \cos \varepsilon + \left(\left(-\sin x \cdot \sin \varepsilon\right) - \cos x\right) & \text{when } \varepsilon \le -1.5194640071230868 \cdot 10^{-06} \\ -(\left(\sin \varepsilon\right) * \left(\sin x\right) + \left(\left(\varepsilon \cdot \varepsilon\right) \cdot \frac{1}{2}\right))_* & \text{when } \varepsilon \le 131297377731453.28 \\ \cos x \cdot \cos \varepsilon + \left(\left(-\sin x \cdot \sin \varepsilon\right) - \cos x\right) & \text{otherwise} \end{cases}\)

    if eps < -1.5194640071230868e-06 or 131297377731453.28 < eps

    1. Started with
      \[\cos \left(x + \varepsilon\right) - \cos x\]
      30.2
    2. Using strategy rm
      30.2
    3. Applied cos-sum to get
      \[\color{red}{\cos \left(x + \varepsilon\right)} - \cos x \leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x\]
      0.9
    4. Using strategy rm
      0.9
    5. Applied sub-neg to get
      \[\color{red}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x \cdot \sin \varepsilon\right)\right)} - \cos x\]
      0.9
    6. Applied associate--l+ to get
      \[\color{red}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x \cdot \sin \varepsilon\right)\right) - \cos x} \leadsto \color{blue}{\cos x \cdot \cos \varepsilon + \left(\left(-\sin x \cdot \sin \varepsilon\right) - \cos x\right)}\]
      0.9

    if -1.5194640071230868e-06 < eps < 131297377731453.28

    1. Started with
      \[\cos \left(x + \varepsilon\right) - \cos x\]
      49.6
    2. Using strategy rm
      49.6
    3. Applied cos-sum to get
      \[\color{red}{\cos \left(x + \varepsilon\right)} - \cos x \leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x\]
      49.0
    4. Using strategy rm
      49.0
    5. Applied add-cube-cbrt to get
      \[\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \color{red}{\sin \varepsilon}\right) - \cos x \leadsto \left(\cos x \cdot \cos \varepsilon - \sin x \cdot \color{blue}{{\left(\sqrt[3]{\sin \varepsilon}\right)}^3}\right) - \cos x\]
      49.0
    6. Applied add-cube-cbrt to get
      \[\left(\cos x \cdot \cos \varepsilon - \color{red}{\sin x} \cdot {\left(\sqrt[3]{\sin \varepsilon}\right)}^3\right) - \cos x \leadsto \left(\cos x \cdot \cos \varepsilon - \color{blue}{{\left(\sqrt[3]{\sin x}\right)}^3} \cdot {\left(\sqrt[3]{\sin \varepsilon}\right)}^3\right) - \cos x\]
      49.0
    7. Applied cube-unprod to get
      \[\left(\cos x \cdot \cos \varepsilon - \color{red}{{\left(\sqrt[3]{\sin x}\right)}^3 \cdot {\left(\sqrt[3]{\sin \varepsilon}\right)}^3}\right) - \cos x \leadsto \left(\cos x \cdot \cos \varepsilon - \color{blue}{{\left(\sqrt[3]{\sin x} \cdot \sqrt[3]{\sin \varepsilon}\right)}^3}\right) - \cos x\]
      49.0
    8. Applied taylor to get
      \[\left(\cos x \cdot \cos \varepsilon - {\left(\sqrt[3]{\sin x} \cdot \sqrt[3]{\sin \varepsilon}\right)}^3\right) - \cos x \leadsto -\left(\frac{1}{2} \cdot {\varepsilon}^2 + {\left(\sqrt[3]{\sin \varepsilon} \cdot \sqrt[3]{\sin x}\right)}^3\right)\]
      1.1
    9. Taylor expanded around 0 to get
      \[\color{red}{-\left(\frac{1}{2} \cdot {\varepsilon}^2 + {\left(\sqrt[3]{\sin \varepsilon} \cdot \sqrt[3]{\sin x}\right)}^3\right)} \leadsto \color{blue}{-\left(\frac{1}{2} \cdot {\varepsilon}^2 + {\left(\sqrt[3]{\sin \varepsilon} \cdot \sqrt[3]{\sin x}\right)}^3\right)}\]
      1.1
    10. Applied simplify to get
      \[-\left(\frac{1}{2} \cdot {\varepsilon}^2 + {\left(\sqrt[3]{\sin \varepsilon} \cdot \sqrt[3]{\sin x}\right)}^3\right) \leadsto -(\left(\sin \varepsilon\right) * \left(\sin x\right) + \left(\left(\varepsilon \cdot \varepsilon\right) \cdot \frac{1}{2}\right))_*\]
      0.1

    11. Applied final simplification

  1. Removed slow pow expressions

Original test:


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