As in Exercise 2, let $\pi$ be an irreducible representation of $\mathrm{sl}(3 ; \mathrm{C})$ and let $\pi^*$ be the dual representation to $\pi$. Show that if $\pi$ has highest weight ( $m_1, m_2$ ), $\pi^*$ has highest weight ( $m_2, m_1$ ).
Hint: Establish this first in the cases $\left(m_1, m_2\right)=(1,0)$ and $\left(m_1, m_2\right)=$ $(0,1)$.