\[\cos \left(x + \varepsilon\right) - \cos x\]
Test:
NMSE problem 3.3.5
Bits:
128 bits
Bits error versus x
Bits error versus eps
Time: 14.3 s
Input Error: 18.0
Output Error: 3.4
Log:
Profile: 🕒
\(\begin{cases} \sqrt[3]{{\left(\cos x\right)}^3 \cdot {\left(\cos \varepsilon\right)}^3} - \left({\left(\sqrt[3]{\sin x \cdot \sin \varepsilon}\right)}^3 + \cos x\right) & \text{when } \varepsilon \le -4.9196116f-11 \\ \left(\varepsilon \cdot \frac{1}{6}\right) \cdot {x}^3 - \varepsilon \cdot \left(\varepsilon \cdot \frac{1}{2} + x\right) & \text{when } \varepsilon \le 4.7023132f-11 \\ \frac{{\left(\cos x \cdot \cos \varepsilon\right)}^2 - {\left(\sin x \cdot \sin \varepsilon + \cos x\right)}^2}{\cos x \cdot \cos \varepsilon + \left(\sin x \cdot \sin \varepsilon + \cos x\right)} & \text{otherwise} \end{cases}\)

    if eps < -4.9196116f-11

    1. Started with
      \[\cos \left(x + \varepsilon\right) - \cos x\]
      17.0
    2. Using strategy rm
      17.0
    3. Applied cos-sum to get
      \[\color{red}{\cos \left(x + \varepsilon\right)} - \cos x \leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x\]
      3.1
    4. Applied associate--l- to get
      \[\color{red}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right) - \cos x} \leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon + \cos x\right)}\]
      3.1
    5. Using strategy rm
      3.1
    6. Applied add-cbrt-cube to get
      \[\cos x \cdot \color{red}{\cos \varepsilon} - \left(\sin x \cdot \sin \varepsilon + \cos x\right) \leadsto \cos x \cdot \color{blue}{\sqrt[3]{{\left(\cos \varepsilon\right)}^3}} - \left(\sin x \cdot \sin \varepsilon + \cos x\right)\]
      3.1
    7. Applied add-cbrt-cube to get
      \[\color{red}{\cos x} \cdot \sqrt[3]{{\left(\cos \varepsilon\right)}^3} - \left(\sin x \cdot \sin \varepsilon + \cos x\right) \leadsto \color{blue}{\sqrt[3]{{\left(\cos x\right)}^3}} \cdot \sqrt[3]{{\left(\cos \varepsilon\right)}^3} - \left(\sin x \cdot \sin \varepsilon + \cos x\right)\]
      3.2
    8. Applied cbrt-unprod to get
      \[\color{red}{\sqrt[3]{{\left(\cos x\right)}^3} \cdot \sqrt[3]{{\left(\cos \varepsilon\right)}^3}} - \left(\sin x \cdot \sin \varepsilon + \cos x\right) \leadsto \color{blue}{\sqrt[3]{{\left(\cos x\right)}^3 \cdot {\left(\cos \varepsilon\right)}^3}} - \left(\sin x \cdot \sin \varepsilon + \cos x\right)\]
      3.2
    9. Using strategy rm
      3.2
    10. Applied add-cube-cbrt to get
      \[\sqrt[3]{{\left(\cos x\right)}^3 \cdot {\left(\cos \varepsilon\right)}^3} - \left(\color{red}{\sin x \cdot \sin \varepsilon} + \cos x\right) \leadsto \sqrt[3]{{\left(\cos x\right)}^3 \cdot {\left(\cos \varepsilon\right)}^3} - \left(\color{blue}{{\left(\sqrt[3]{\sin x \cdot \sin \varepsilon}\right)}^3} + \cos x\right)\]
      3.3

    if -4.9196116f-11 < eps < 4.7023132f-11

    1. Started with
      \[\cos \left(x + \varepsilon\right) - \cos x\]
      20.5
    2. Applied taylor to get
      \[\cos \left(x + \varepsilon\right) - \cos x \leadsto \frac{1}{6} \cdot \left(\varepsilon \cdot {x}^{3}\right) - \left(\frac{1}{2} \cdot {\varepsilon}^2 + \varepsilon \cdot x\right)\]
      4.1
    3. Taylor expanded around 0 to get
      \[\color{red}{\frac{1}{6} \cdot \left(\varepsilon \cdot {x}^{3}\right) - \left(\frac{1}{2} \cdot {\varepsilon}^2 + \varepsilon \cdot x\right)} \leadsto \color{blue}{\frac{1}{6} \cdot \left(\varepsilon \cdot {x}^{3}\right) - \left(\frac{1}{2} \cdot {\varepsilon}^2 + \varepsilon \cdot x\right)}\]
      4.1
    4. Applied simplify to get
      \[\color{red}{\frac{1}{6} \cdot \left(\varepsilon \cdot {x}^{3}\right) - \left(\frac{1}{2} \cdot {\varepsilon}^2 + \varepsilon \cdot x\right)} \leadsto \color{blue}{\left(\varepsilon \cdot \frac{1}{6}\right) \cdot {x}^3 - \varepsilon \cdot \left(\varepsilon \cdot \frac{1}{2} + x\right)}\]
      4.1

    if 4.7023132f-11 < eps

    1. Started with
      \[\cos \left(x + \varepsilon\right) - \cos x\]
      16.7
    2. Using strategy rm
      16.7
    3. Applied cos-sum to get
      \[\color{red}{\cos \left(x + \varepsilon\right)} - \cos x \leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x\]
      2.9
    4. Applied associate--l- to get
      \[\color{red}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right) - \cos x} \leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon + \cos x\right)}\]
      2.9
    5. Using strategy rm
      2.9
    6. Applied flip-- to get
      \[\color{red}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon + \cos x\right)} \leadsto \color{blue}{\frac{{\left(\cos x \cdot \cos \varepsilon\right)}^2 - {\left(\sin x \cdot \sin \varepsilon + \cos x\right)}^2}{\cos x \cdot \cos \varepsilon + \left(\sin x \cdot \sin \varepsilon + \cos x\right)}}\]
      2.9

  1. Removed slow pow expressions

Original test:


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