- Started with
\[\cos \left(x + \varepsilon\right) - \cos x\]
61.1
- Using strategy
rm 61.1
- Applied cos-sum to get
\[\color{red}{\cos \left(x + \varepsilon\right)} - \cos x \leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x\]
60.3
- Applied associate--l- to get
\[\color{red}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right) - \cos x} \leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon + \cos x\right)}\]
60.3
- Using strategy
rm 60.3
- Applied add-cbrt-cube to get
\[\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \color{red}{\sin \varepsilon} + \cos x\right) \leadsto \cos x \cdot \cos \varepsilon - \left(\sin x \cdot \color{blue}{\sqrt[3]{{\left(\sin \varepsilon\right)}^3}} + \cos x\right)\]
60.3
- Applied add-cbrt-cube to get
\[\cos x \cdot \cos \varepsilon - \left(\color{red}{\sin x} \cdot \sqrt[3]{{\left(\sin \varepsilon\right)}^3} + \cos x\right) \leadsto \cos x \cdot \cos \varepsilon - \left(\color{blue}{\sqrt[3]{{\left(\sin x\right)}^3}} \cdot \sqrt[3]{{\left(\sin \varepsilon\right)}^3} + \cos x\right)\]
60.3
- Applied cbrt-unprod to get
\[\cos x \cdot \cos \varepsilon - \left(\color{red}{\sqrt[3]{{\left(\sin x\right)}^3} \cdot \sqrt[3]{{\left(\sin \varepsilon\right)}^3}} + \cos x\right) \leadsto \cos x \cdot \cos \varepsilon - \left(\color{blue}{\sqrt[3]{{\left(\sin x\right)}^3 \cdot {\left(\sin \varepsilon\right)}^3}} + \cos x\right)\]
60.3
- Applied taylor to get
\[\cos x \cdot \cos \varepsilon - \left(\sqrt[3]{{\left(\sin x\right)}^3 \cdot {\left(\sin \varepsilon\right)}^3} + \cos x\right) \leadsto -\left(\frac{1}{2} \cdot {\varepsilon}^2 + \sqrt[3]{{\left(\sin x\right)}^3 \cdot {\left(\sin \varepsilon\right)}^3}\right)\]
9.4
- Taylor expanded around 0 to get
\[\color{red}{-\left(\frac{1}{2} \cdot {\varepsilon}^2 + \sqrt[3]{{\left(\sin x\right)}^3 \cdot {\left(\sin \varepsilon\right)}^3}\right)} \leadsto \color{blue}{-\left(\frac{1}{2} \cdot {\varepsilon}^2 + \sqrt[3]{{\left(\sin x\right)}^3 \cdot {\left(\sin \varepsilon\right)}^3}\right)}\]
9.4