## Numerical Methods for Engineers

$$\mu=\frac{\ln 2}{20}$$ also, see the following image:
Solve the simple given equation to obtain $$N(t)=N_{0} e^{\mu t}$$ where $N_{0}=N(0)$ In order to determine $\mu$ , use the given information $N(20)=2 N(0)$ \begin{array}{c}{N_{0} e^{20 \mu}=2 \cdot N_{0} e^{0 \mu}} \\ {\Leftrightarrow e^{20 \mu}=2} \\ {\Leftrightarrow 20 \mu=\ln 2}\end{array} $$\mu=\frac{\ln 2}{20}$$