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# Stuck on differentiation watch

1. I did this in the exam in January, but can't seem to do it now

I = 16 - 16 (0.5^t)

find dI/dt when t=3.

I've totally forgotten how to differentiate this. Can anyone help?
2. For you can write , which you can differentiate using the chain rule.
3. (Original post by chaz1992)
I did this in the exam in January, but can't seem to do it now

I = 16 - 16 (0.5^t)

find dI/dt when t=3.

I've totally forgotten how to differentiate this. Can anyone help?
Note that . Then differentiate like you would any exponential.
4. (Original post by nuodai)
For you can write , which you can differentiate using the chain rule.
That's a really nice way of doing it, never of thought of that.
5. Thanks for the help guys. Thumbs up given.

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