TeX source:

\begin{aligned} \lim\limits_{h \rightarrow 0} \sin (a+h) &=\lim\limits_{h \rightarrow 0} \sin (a) \cos (\mathrm{h})+\cos (a) \sin (h) \\ &=\lim\limits_{h \rightarrow 0} \sin (a) \cdot \lim\limits_{h \rightarrow 0} \cos (\mathrm{h})+\lim\limits_{h \rightarrow 0} \cos (\mathrm{a}) \cdot \lim\limits_{h \rightarrow 0} \sin (\mathrm{h}) \end{aligned}