Let l be the length and l be the height of the generatrix of the cone, and let two generatrix passing through the cone make a section to get the maximum area of the section

Let l be the length and l be the height of the generatrix of the cone, and let two generatrix passing through the cone make a section to get the maximum area of the section

From the length and height of the generatrix, it can be seen that the axial section is an isosceles triangle with the angle of 120 & ordm; as the vertex angle, while the section with the largest area is the section passing through two mutually perpendicular generatrix, and the largest area is L & sup2 / 2
(when the vertex angle of an isosceles triangle is less than 90 & ordm;, the section with the largest area is an axis section; when the vertex angle of an isosceles triangle is not less than 90 & ordm;, the section passing through two mutually perpendicular generatrix is the section with the largest area.)