
 [No title] 
  \medskip Prove that the equation of a line in barycentric coordinates is of the form $$ux + vy + wz = 0,$$ where $u\not= v$, or $v\not= w$, or $u\not= w$. 
  In either case, let $(m, m', m'')$ be the barycentric coordinates of $M$, as explained at the beginning of the problem. 
  In the affine plane $\affreal^2$, a {\it conic\/} is the set of points of coordinates $(x, y)$ such that \[ \alpha x^2 + \beta y^2 + 2\gamma xy + 2\delta x + 2\lambda y + \mu = 0, \] where $\alpha\not= 0$ or $\beta\not= 0$ or $\gamma\not= 0$. 
 www.cis.upenn.edu /~cis610/cis61006hw1 (2329 words) 
