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# AS level logarithms watch

1. Please could someone explain how to work this out in terms of logs:

e^-0.05t = 275/400
2. (Original post by rxch_x)
Please could someone explain how to work this out in terms of logs:

e^-0.05t = 275/400
Well, what do you need to do to both sides to cancel the exponentiation on the left?
3. (Original post by RDKGames)
Well, what do you need to do to both sides to cancel the exponentiation on the left?
would this be correct (I’m not sure if it’s the easiest method to use)?
ln275/400 = -0.37469...
-0.37469/-0.05 = 7.49 (3 sf)
4. (Original post by rxch_x)
would this be correct (I’m not sure if it’s the easiest method to use)?
ln275/400 = -0.37469...
-0.37469/-0.05 = 7.49 (3 sf)
That's right, though you should keep the answer in exact form without rounding, unless you need to.
5. (Original post by rxch_x)
would this be correct (I’m not sure if it’s the easiest method to use)?
ln275/400 = -0.37469...
-0.37469/-0.05 = 7.49 (3 sf)
it looks correct

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