Question

Find derivatives of the functions defined as follows. p=\frac{1000}{9+4e^{-0.2t}}

Composite functions
$$\displaystyle{p}={\frac{{{1000}}}{{{9}+{4}{e}^{{-{0.2}{t}}}}}}$$
$$\displaystyle{\frac{{{d}{p}}}{{{\left.{d}{t}\right.}}}}={8000}{\left({9}+{4}{e}^{{-{0.2}{t}}}\right)}^{{{2}}}{e}^{{-{0.2}{t}}}$$