{{{id=1|
t = var('t')

yo = var('yo')

k = var('k')

y(t) = yo*e^(k*t)

#where k is as a constant

y(5730) = 0.5*yo

log(0.5, e) = 5730*k 

#=>

k = log(0.5, e)/5730 =  
-0.693147180559945 / 5730

print k
///
k

{{{id=2| k = -0.693147180559945 / 5730 print k /// -0.000120968094338559 }}}

{{{id=3| # no y(3000)/yo = exp(k*3000) /// 0.695653016121338 }}}

{{{id=4| #y(3000) = 0.69*yo # which is 69% of the initial content /// }}} }}}

SageDays/Kreyszig-1.4-5 (last edited 2010-08-10 12:06:34 by bhanukiran)