1. The problem statement, all variables and given/known data As long as N isn't too small, the growth of cancerous tumors can be modeled by the Gompertz equation, dN/dt = -rN*ln(N/K), where N(t) is proportional to the number of cells in the tumor, and r,K>0 are parameters. 2. Relevant equations 3. The attempt at a solution Separate out. dN/[N*ln(N/K)]= -rdt After much toil, I figured out that the left side is simply d/dN (ln(ln(N/K)) ==> ln(ln(N/K)) = -rt + C ==> ln(N/K) = e-rt+C ==> N/K = ee-rt+C ==> N = Kee-rt+C Seems overly complicated. Is there some property of ln(ln(f)) that would help simplify? Suggestions, please.