Problem
\( \frac{d f}{d t}=\lim _{h \rightarrow 0} \frac{f(t+h)-f(t)}{h} \)
Solution
Step 1 ：\( \frac{d f}{d t}=\lim _{h \rightarrow 0} \frac{f(t+h)-f(t)}{h} \)
Step 1 ：\( \frac{d f}{d t}=\lim _{h \rightarrow 0} \frac{f(t+h)-f(t)}{h} \)
