\[\cos \left(x + \varepsilon\right) - \cos x\]
Test:
NMSE problem 3.3.5
Bits:
128 bits
Bits error versus x
Bits error versus eps
Time: 8.3 s
Input Error: 17.6
Output Error: 2.6
Log: ⚲
Profile: 🕒
\(\begin{cases} \left(\sqrt[3]{{\left(\cos x\right)}^3 \cdot {\left(\cos \varepsilon\right)}^3} - \sin x \cdot \sin \varepsilon\right) - \cos x & \text{when } \varepsilon \le -9.268573f-09 \\ \left(\varepsilon \cdot \frac{1}{6}\right) \cdot {x}^3 - \varepsilon \cdot (\frac{1}{2} * \varepsilon + x)_* & \text{when } \varepsilon \le 0.25760502f0 \\ \left(\sqrt[3]{{\left(\cos x\right)}^3 \cdot {\left(\cos \varepsilon\right)}^3} - \sin x \cdot \sin \varepsilon\right) - \cos x & \text{otherwise} \end{cases}\)

    if eps < -9.268573f-09 or 0.25760502f0 < eps

    1. Started with
      \[\cos \left(x + \varepsilon\right) - \cos x\]
      15.2
    2. Using strategy rm
      15.2
    3. Applied cos-sum to get
      \[\color{red}{\cos \left(x + \varepsilon\right)} - \cos x \leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x\]
      1.7
    4. Using strategy rm
      1.7
    5. Applied add-cbrt-cube to get
      \[\left(\cos x \cdot \color{red}{\cos \varepsilon} - \sin x \cdot \sin \varepsilon\right) - \cos x \leadsto \left(\cos x \cdot \color{blue}{\sqrt[3]{{\left(\cos \varepsilon\right)}^3}} - \sin x \cdot \sin \varepsilon\right) - \cos x\]
      1.7
    6. Applied add-cbrt-cube to get
      \[\left(\color{red}{\cos x} \cdot \sqrt[3]{{\left(\cos \varepsilon\right)}^3} - \sin x \cdot \sin \varepsilon\right) - \cos x \leadsto \left(\color{blue}{\sqrt[3]{{\left(\cos x\right)}^3}} \cdot \sqrt[3]{{\left(\cos \varepsilon\right)}^3} - \sin x \cdot \sin \varepsilon\right) - \cos x\]
      1.7
    7. Applied cbrt-unprod to get
      \[\left(\color{red}{\sqrt[3]{{\left(\cos x\right)}^3} \cdot \sqrt[3]{{\left(\cos \varepsilon\right)}^3}} - \sin x \cdot \sin \varepsilon\right) - \cos x \leadsto \left(\color{blue}{\sqrt[3]{{\left(\cos x\right)}^3 \cdot {\left(\cos \varepsilon\right)}^3}} - \sin x \cdot \sin \varepsilon\right) - \cos x\]
      1.8

    if -9.268573f-09 < eps < 0.25760502f0

    1. Started with
      \[\cos \left(x + \varepsilon\right) - \cos x\]
      21.7
    2. Applied taylor to get
      \[\cos \left(x + \varepsilon\right) - \cos x \leadsto \frac{1}{6} \cdot \left(\varepsilon \cdot {x}^{3}\right) - \left(\frac{1}{2} \cdot {\varepsilon}^2 + \varepsilon \cdot x\right)\]
      3.9
    3. Taylor expanded around 0 to get
      \[\color{red}{\frac{1}{6} \cdot \left(\varepsilon \cdot {x}^{3}\right) - \left(\frac{1}{2} \cdot {\varepsilon}^2 + \varepsilon \cdot x\right)} \leadsto \color{blue}{\frac{1}{6} \cdot \left(\varepsilon \cdot {x}^{3}\right) - \left(\frac{1}{2} \cdot {\varepsilon}^2 + \varepsilon \cdot x\right)}\]
      3.9
    4. Applied simplify to get
      \[\color{red}{\frac{1}{6} \cdot \left(\varepsilon \cdot {x}^{3}\right) - \left(\frac{1}{2} \cdot {\varepsilon}^2 + \varepsilon \cdot x\right)} \leadsto \color{blue}{\left(\varepsilon \cdot \frac{1}{6}\right) \cdot {x}^3 - \varepsilon \cdot (\frac{1}{2} * \varepsilon + x)_*}\]
      3.9
  1. Removed slow pow expressions

Original test:


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