\[\cos \left(x + \varepsilon\right) - \cos x\]
Test:
NMSE problem 3.3.5
Bits:
128 bits
Bits error versus x
Bits error versus eps
Time: 17.1 s
Input Error: 18.3
Output Error: 0.7
Log:
Profile: 🕒
\(\begin{cases} {\left(\cos x \cdot \cos \varepsilon\right)}^{1} - \left(\sin x \cdot \sin \varepsilon + \cos x\right) & \text{when } \varepsilon \le -0.00030713418f0 \\ \left(\varepsilon \cdot \frac{-1}{2}\right) \cdot \varepsilon - \sin \varepsilon \cdot \sin x & \text{when } \varepsilon \le 0.0017607713f0 \\ \cos x \cdot \cos \varepsilon - \left({\left(\sqrt[3]{\sin x} \cdot \sqrt[3]{\sin \varepsilon}\right)}^3 + \cos x\right) & \text{otherwise} \end{cases}\)

    if eps < -0.00030713418f0

    1. Started with
      \[\cos \left(x + \varepsilon\right) - \cos x\]
      14.6
    2. Using strategy rm
      14.6
    3. Applied cos-sum to get
      \[\color{red}{\cos \left(x + \varepsilon\right)} - \cos x \leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x\]
      1.2
    4. Applied associate--l- to get
      \[\color{red}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right) - \cos x} \leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon + \cos x\right)}\]
      1.2
    5. Using strategy rm
      1.2
    6. Applied pow1 to get
      \[\cos x \cdot \color{red}{\cos \varepsilon} - \left(\sin x \cdot \sin \varepsilon + \cos x\right) \leadsto \cos x \cdot \color{blue}{{\left(\cos \varepsilon\right)}^{1}} - \left(\sin x \cdot \sin \varepsilon + \cos x\right)\]
      1.2
    7. Applied pow1 to get
      \[\color{red}{\cos x} \cdot {\left(\cos \varepsilon\right)}^{1} - \left(\sin x \cdot \sin \varepsilon + \cos x\right) \leadsto \color{blue}{{\left(\cos x\right)}^{1}} \cdot {\left(\cos \varepsilon\right)}^{1} - \left(\sin x \cdot \sin \varepsilon + \cos x\right)\]
      1.2
    8. Applied pow-prod-down to get
      \[\color{red}{{\left(\cos x\right)}^{1} \cdot {\left(\cos \varepsilon\right)}^{1}} - \left(\sin x \cdot \sin \varepsilon + \cos x\right) \leadsto \color{blue}{{\left(\cos x \cdot \cos \varepsilon\right)}^{1}} - \left(\sin x \cdot \sin \varepsilon + \cos x\right)\]
      1.2

    if -0.00030713418f0 < eps < 0.0017607713f0

    1. Started with
      \[\cos \left(x + \varepsilon\right) - \cos x\]
      22.8
    2. Using strategy rm
      22.8
    3. Applied cos-sum to get
      \[\color{red}{\cos \left(x + \varepsilon\right)} - \cos x \leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x\]
      18.7
    4. Applied associate--l- to get
      \[\color{red}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right) - \cos x} \leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon + \cos x\right)}\]
      18.7
    5. Using strategy rm
      18.7
    6. Applied flip-- to get
      \[\color{red}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon + \cos x\right)} \leadsto \color{blue}{\frac{{\left(\cos x \cdot \cos \varepsilon\right)}^2 - {\left(\sin x \cdot \sin \varepsilon + \cos x\right)}^2}{\cos x \cdot \cos \varepsilon + \left(\sin x \cdot \sin \varepsilon + \cos x\right)}}\]
      18.7
    7. Using strategy rm
      18.7
    8. Applied add-exp-log to get
      \[\color{red}{\frac{{\left(\cos x \cdot \cos \varepsilon\right)}^2 - {\left(\sin x \cdot \sin \varepsilon + \cos x\right)}^2}{\cos x \cdot \cos \varepsilon + \left(\sin x \cdot \sin \varepsilon + \cos x\right)}} \leadsto \color{blue}{e^{\log \left(\frac{{\left(\cos x \cdot \cos \varepsilon\right)}^2 - {\left(\sin x \cdot \sin \varepsilon + \cos x\right)}^2}{\cos x \cdot \cos \varepsilon + \left(\sin x \cdot \sin \varepsilon + \cos x\right)}\right)}}\]
      21.1
    9. Applied simplify to get
      \[e^{\color{red}{\log \left(\frac{{\left(\cos x \cdot \cos \varepsilon\right)}^2 - {\left(\sin x \cdot \sin \varepsilon + \cos x\right)}^2}{\cos x \cdot \cos \varepsilon + \left(\sin x \cdot \sin \varepsilon + \cos x\right)}\right)}} \leadsto e^{\color{blue}{\log \left(\left(\cos \varepsilon \cdot \cos x - \cos x\right) - \sin x \cdot \sin \varepsilon\right)}}\]
      17.1
    10. Applied taylor to get
      \[e^{\log \left(\left(\cos \varepsilon \cdot \cos x - \cos x\right) - \sin x \cdot \sin \varepsilon\right)} \leadsto e^{\log \left(\frac{-1}{2} \cdot {\varepsilon}^2 - \sin x \cdot \sin \varepsilon\right)}\]
      17.3
    11. Taylor expanded around 0 to get
      \[e^{\log \left(\color{red}{\frac{-1}{2} \cdot {\varepsilon}^2} - \sin x \cdot \sin \varepsilon\right)} \leadsto e^{\log \left(\color{blue}{\frac{-1}{2} \cdot {\varepsilon}^2} - \sin x \cdot \sin \varepsilon\right)}\]
      17.3
    12. Applied simplify to get
      \[e^{\log \left(\frac{-1}{2} \cdot {\varepsilon}^2 - \sin x \cdot \sin \varepsilon\right)} \leadsto \left(\varepsilon \cdot \frac{-1}{2}\right) \cdot \varepsilon - \sin \varepsilon \cdot \sin x\]
      0.1

    13. Applied final simplification

    if 0.0017607713f0 < eps

    1. Started with
      \[\cos \left(x + \varepsilon\right) - \cos x\]
      14.1
    2. Using strategy rm
      14.1
    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. Applied associate--l- to get
      \[\color{red}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right) - \cos x} \leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon + \cos x\right)}\]
      0.9
    5. Using strategy rm
      0.9
    6. Applied add-cube-cbrt to get
      \[\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \color{red}{\sin \varepsilon} + \cos x\right) \leadsto \cos x \cdot \cos \varepsilon - \left(\sin x \cdot \color{blue}{{\left(\sqrt[3]{\sin \varepsilon}\right)}^3} + \cos x\right)\]
      1.0
    7. Applied add-cube-cbrt to get
      \[\cos x \cdot \cos \varepsilon - \left(\color{red}{\sin x} \cdot {\left(\sqrt[3]{\sin \varepsilon}\right)}^3 + \cos x\right) \leadsto \cos x \cdot \cos \varepsilon - \left(\color{blue}{{\left(\sqrt[3]{\sin x}\right)}^3} \cdot {\left(\sqrt[3]{\sin \varepsilon}\right)}^3 + \cos x\right)\]
      1.1
    8. Applied cube-unprod to get
      \[\cos x \cdot \cos \varepsilon - \left(\color{red}{{\left(\sqrt[3]{\sin x}\right)}^3 \cdot {\left(\sqrt[3]{\sin \varepsilon}\right)}^3} + \cos x\right) \leadsto \cos x \cdot \cos \varepsilon - \left(\color{blue}{{\left(\sqrt[3]{\sin x} \cdot \sqrt[3]{\sin \varepsilon}\right)}^3} + \cos x\right)\]
      1.1

  1. Removed slow pow expressions

Original test:


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