# Math Insight

### Applet: Bacteria density versus time along with exponential growth fit

The growth of the bacteria population density is compared with an exponential growth model. The data is displayed by the blue circles. The exponential growth model can be either written in difference form as $$B_{t+1} - B_t = r B_t$$ or in function iteration form as $$B_{t+1} = R B_t,$$ where the two growth parameters related by $R=r+1$. You can change either growth parameter $r$ or $R$ by typing a value in the corresponding box. The other parameter will be updated automatically. The model results are are displayed by the red crosses. For a certain value of $r$ or $R$, the model results should fit the data fairly closely.

Applet file: bacteria_density_versus_time_with_fit.ggb