- Started with
\[\cos \left(x + \varepsilon\right) - \cos x\]
22.7
- Using strategy
rm 22.7
- Applied cos-sum to get
\[\color{red}{\cos \left(x + \varepsilon\right)} - \cos x \leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x\]
18.5
- Using strategy
rm 18.5
- Applied log1p-expm1-u to get
\[\left(\cos x \cdot \cos \varepsilon - \color{red}{\sin x \cdot \sin \varepsilon}\right) - \cos x \leadsto \left(\cos x \cdot \cos \varepsilon - \color{blue}{\log_* (1 + (e^{\sin x \cdot \sin \varepsilon} - 1)^*)}\right) - \cos x\]
18.5
- Applied taylor to get
\[\left(\cos x \cdot \cos \varepsilon - \log_* (1 + (e^{\sin x \cdot \sin \varepsilon} - 1)^*)\right) - \cos x \leadsto -\left(\frac{1}{2} \cdot {\varepsilon}^2 + \log_* (1 + (e^{\sin x \cdot \sin \varepsilon} - 1)^*)\right)\]
0.2
- Taylor expanded around 0 to get
\[\color{red}{-\left(\frac{1}{2} \cdot {\varepsilon}^2 + \log_* (1 + (e^{\sin x \cdot \sin \varepsilon} - 1)^*)\right)} \leadsto \color{blue}{-\left(\frac{1}{2} \cdot {\varepsilon}^2 + \log_* (1 + (e^{\sin x \cdot \sin \varepsilon} - 1)^*)\right)}\]
0.2
- Applied simplify to get
\[\color{red}{-\left(\frac{1}{2} \cdot {\varepsilon}^2 + \log_* (1 + (e^{\sin x \cdot \sin \varepsilon} - 1)^*)\right)} \leadsto \color{blue}{(\left(-\sin x\right) * \left(\sin \varepsilon\right) + \left(\left(-\varepsilon\right) \cdot \left(\varepsilon \cdot \frac{1}{2}\right)\right))_*}\]
0.1
- Applied simplify to get
\[(\left(-\sin x\right) * \left(\sin \varepsilon\right) + \color{red}{\left(\left(-\varepsilon\right) \cdot \left(\varepsilon \cdot \frac{1}{2}\right)\right)})_* \leadsto (\left(-\sin x\right) * \left(\sin \varepsilon\right) + \color{blue}{\left({\varepsilon}^2 \cdot \left(-\frac{1}{2}\right)\right)})_*\]
0.1