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\begin{aligned}&\mathrm{m}_{\tan }=\lim\limits_{h \rightarrow 0} \mathrm{~m}_{\mathrm{sec}}=\lim\limits_{h \rightarrow 0} \frac{f(2+h)-f(2)}{(2+h)-(2)} \\&=\lim\limits_{h \rightarrow 0} \frac{(2+h)^{2}-(2)^{2}}{(2+h)-(2)}=\lim _{h \rightarrow 0} \frac{4+4 h+h^{2}-4}{h} \\&=\lim\limits_{h \rightarrow 0} \frac{4 h+h^{2}}{h}=\lim _{h \rightarrow 0} \frac{h(4+h)}{h}=\lim\limits_{h \rightarrow 0}(4+h)=4\end{aligned}