Question 89
Given two hyperbolae $H_1$ and $H_2$ with the equations $y = 1/x$ and $y = -1/x$, respectively. A straight line meets $H_1$ at points $A$ and $B$, and meets $H_2$ at points $C$ and $D$. Let $O$ be the origin of coordinates.
Prove that the areas of the triangles $OAC$ and $OBD$ are equal. (S. Mazanik)
Prove that the areas of the triangles $OAC$ and $OBD$ are equal. (S. Mazanik)