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## Homework Statement

boat turns off engine when it's attained [itex]v_0[/itex] at [itex]t = 0[/itex]. Starting from that moment the boat is slowed by retarding force [itex]F = Ce^{-kv}[/itex]

## The Attempt at a Solution

[tex]m\dot{v} = -Ce^{-kv}[/tex]

Throwing this in Maple gives me

[tex]v(t) = \frac{1}{k}\ln\left(\frac{-kC(t + C^{'})}{m}\right)[/tex]

This doesn't make sense to me--you can't take the log of a negative number and even if I remove that negative from the initial DE v(t)->inf as t->inf