Let \( f(x)=3\sqrt{x-2}+\sqrt{4-x} \) be a real valued function. If \( \alpha \) and \( \beta \) are respectively the minimum and the maximum values of \( f \), then \( \alpha^2+2\beta^2 \) is equal to:
\( 42 \)
\( 38 \)
\( 24 \)
\( 44 \)