Samples of the solutions::

Octave or Matlab code

i=1; figure;hold on;

while i<5

\(\displaystyle{P}{0}={10}^{{i}}\);

t=linspace(0,100,100000)';

\(\displaystyle{\left[{t},{P}\right]}={o}{d}{e}{45}{\left(\circ{\left({t},{P}\right)}{0.05}\cdot{P}.\cdot{\log{{\left({1000}\frac{.}{{P}}\right)}}},{t},{P}{0}\right)}\);

plot(t,P);

i=i+1;

endwhile;

legend\(("P_0=10","P_0=100","P_0=1000","P_0=10000")\);

[Graph]