Answer
$\frac{1}{2}.$
Work Step by Step
We have
\begin{align*} \lim _{t \rightarrow \infty}\frac{t^{4/3}-9t^{1/3}}{(8t^{4}+2)^{1/3}} &= \lim _{t \rightarrow \infty}\frac{t^{4/3}(1-9t^{-1})}{t^{4/3}(8+2t^{-4})^{1/3}} \\ &=\frac{(1-0)}{(8+0)^{1/3}} \\
&=\frac{1}{2}.
\end{align*}