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# Logs Help!! watch

1. This is the question:
A model for future trading predicts that profits will increase year by year in a geometric sequence with common ratio r, r>1

The model predicts that in Year n, the profit made will exceed £200,000

Show that n > (log 4)/(log r) + 1

2. bump
3. A geometrical sequence is one where the next term is found by multiplying the previous term by a constant multiplier, r.

So the sequence is:

Note that the first term a = £50,000 is year one and the power of r I would have put in the above sequence is zero if I didn't omit it for simplicity.

Therefore, in each term r is raised to the power of (n - 1) where n is the year number.

To exceed £200,000,

You can then log both sides to bring (n-1) down and use the log rules to rearrange to give the final answer.

Hope that helped.
4. I understand now!
Thank you

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Updated: March 16, 2011
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