What is the general formula for exponential growth of a population?

1 Answer
Mar 2, 2018

Population [P]= Ce^[kt[P]=Cekt

Explanation:

If the rate of growth PP is proportional to itself, then with respect to time tt,

[dP]/dt=kPdPdt=kP, ....inverting both sides, .....dt/[dP]=[1]/[kPdtdP=1kP and so integrating both sides

intdt=int[dP]/[kPdt=dPkP, thus,..... t=1/klnP +t=1klnP+ a constant............[1][1]

Suppose PP is some value CC when t=0t=0, substituting

0=1/klnC+0=1klnC+ constant, therefore the constant = -1/klnC=1klnC and so substituting this value for the constant in ...[1][1] we have ,

t= 1/k[ln P-lnC]t=1k[lnPlnC] = 1/k ln[P/C]1kln[PC], therefore , kt=ln[p/C]kt=ln[pC][ theory of logs] and so

e^[kt]=P/Cekt=PC......giving P=Ce^[ktP=Cekt. The constant kk will represent the excess of births over deaths or vice versa for a decreasing rate.