$\therefore$ Given a cone with vertex $V$, the diameter of the base $\mathrm{E}$ is $A B$, its generatrix length is $l$, and the angle between the two generatrices in the axial section is $\alpha$, then the maximum area of the section passing through the two generatrices of the cone is
8. $\frac{1}{2} l^{2}$.

It is easy to find that when $0^{\circ}<\alpha<90^{\circ}$, the maximum area sought is $\frac{1}{2} l^{2} \sin \alpha$; when $90^{\circ} \leqslant \alpha<180^{\circ}$, the maximum area sought is $\frac{1}{2} l^{2}$.