1. Help with differentiate functions

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....

2. Originally Posted by rhcp1231
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 $y = \left(\frac{2}{3}\right)^t$, then

$\ln y = t \ln \left(\frac{2}{3}\right)$

differentiate both side with respect to t

$\frac{1}{y} \frac{dy}{dt} = \ln \left(\frac{2}{3}\right)$

or

$\frac{dy}{dt} = y \ln \left(\frac{2}{3}\right) = \left(\frac{2}{3}\right)^t \ln \left(\frac{2}{3}\right)$