hi i was wondering if anyone knew how to introduce different populations at diffrent times on the same plot on mathematica? Say i wanted population 1 have n = 10 at t=0, population 2 to have n=4 at t=0 and then introduce a new population at t=25 so that population 3 would have n= 0 initally but then n= 1 at t = 25. Any ideas? the only way I've been gettting around it is to give population 3 really small values initially (e.g. 0.000000000001) but its not very precise.