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# Rates of change watch

1. The number of bacteria present in a culture is modelled by y = yoe^(kt), where k>0 and t is the number of hours after 12 noon. At 1:00 pm the bacteria has doubled.

a) According to the formula how many bacteria are present at 12 noon?

How do you work this out?
2. (Original post by Custardcream000)
The number of bacteria present in a culture is modelled by y = yoe^(kt), where k>0 and t is the number of hours after 12 noon. At 1:00 pm the bacteria has doubled.

a) According to the formula how many bacteria are present at 12 noon?

How do you work this out?
is the number of hours after 12 noon. So the number of bacteria present at 12 noon would be when .
3. YInitial=yo
Ydouble=yoe^K
Ln2y/y=k
K=ln2

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Updated: January 12, 2017
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