Specific growth rate

Relative growth rate (RGR) is the growth rate relative to the size of the population. It is also called the exponential growth rate, or the continuous growth rate. In terms of differential equations, if ${\displaystyle P}$ is the population, and ${\displaystyle {\frac {dP}{dt}}}$ its growth rate, then its relative growth rate is ${\displaystyle {\frac {1}{P}}{\frac {dP}{dt}}}$. If the relative growth rate is constant, i.e., ${\displaystyle {\frac {1}{P}}{\frac {dP}{dt}}=k}$, it is not difficult to verify that a solution to this equation is ${\displaystyle P(t)=\exp(kt)}$. When calculating or discussing relative growth rate, it is important to pay attention to the units of time being considered.

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