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# Decay constants Watch

1. Okay only need reassurance about this as I have a rough idea but i'm not 100% certain

but say you are give an equation that follows

n= n'e^-kt

and you are given n, n' and t when rearranging and after using logs you end up with

log n = -kt

If you flip the equation do you end up with

log (1/n) = kt

Many thanks
Jacobdatz
2. (Original post by Jacobdatz)
Okay only need reassurance about this as I have a rough idea but i'm not 100% certain

but say you are give an equation that follows

n= n'e^-kt

and you are given n, n' and t when rearranging and after using logs you end up with

log n = -kt

If you flip the equation do you end up with

log (1/n) = kt

Many thanks
Jacobdatz
Yes, more or less.
If you rearrange and log that equation you get
log (n/n') = -kt
Inverting gives
log (n'/n) = kt

The rule is that if log n = x then log (1/n) = -x

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Updated: December 8, 2010
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