Question

Deriv of
r= 8^-t ?

Answer 1

is it -8^-t?

Answer 2

No. Don't forget the chain rule. :D
(Or just pull it off a table because it's simple)

Answer 3

what is it then? ): lol

Answer 4

\[-8^{-t}\ln 8\]
You can prove that by rewriting it in terms of \(e\) but it's easy enough to just remember, too.

Answer 5

You can probably generalize it as \(\frac{d}{dx}n^x = \frac{x}{|x|}n^x\ln n\) but I haven't thought that through 100%