Re: poly: Seeking StarFlight Functional Forms

From: Robin Hanson <hanson@econ.berkeley.edu>
Date: Thu Feb 05 1998 - 12:19:24 PST

Damien asks:
>Care to tell us your reasons? It might help get us into the spirit of
>things.
>
>> R(s) = exp(lnR(s)), lnR'(s) = lnR0 - lnRd*s.
>> A(x) = exp(lnA(x)), lnA'(x) = lnA0 + lnAd*x.
>
>I've having trouble with these two. R=exp(ln(R))? R=R? I assume R' is
>R-prime, or dR/dt. (Or dR/ds, I suppose.)

"lnR" is a distinct symbol naming a new function. The equation
says that the (exponential) growth rate declines linearly with time for R.
For A the exponential kill rate increases linearly with distance. With
more distance,not only might you hit a big object in your path, but the
accumulation of small hits over your whole flight might finally kill you off.

Robin Hanson
hanson@econ.berkeley.edu http://hanson.berkeley.edu/
RWJF Health Policy Scholar, Sch. of Public Health 510-643-1884
140 Warren Hall, UC Berkeley, CA 94720-7360 FAX: 510-643-8614
Received on Thu Feb 5 20:22:38 1998

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