Write the MATLAB statements required to calculate $y(t)$ from the equation
$$
y(t)= \begin{cases}-3 t^{2}+5 & t \geq 0 \\ 3 t^{2}+5 & t<0\end{cases}
$$
for values of $t$ between $-9$ and 9 in steps of $0.5$. Use loops and branches to perform this calculation.