how would i go about finding the differentiate of:
f(t) = 2-(2/3)t
i know the power rule and all that but i just dont know where to start....
let $\displaystyle y = \left(\frac{2}{3}\right)^t$, then
$\displaystyle \ln y = t \ln \left(\frac{2}{3}\right)$
differentiate both side with respect to t
$\displaystyle \frac{1}{y} \frac{dy}{dt} = \ln \left(\frac{2}{3}\right)$
or
$\displaystyle \frac{dy}{dt} = y \ln \left(\frac{2}{3}\right) = \left(\frac{2}{3}\right)^t \ln \left(\frac{2}{3}\right)$
now,..solve your problem