Write expression for all points enclosed by 2 vectors?

Let P and Q denote two 2 dimensional vectors. Line segment L which joins P and Q can be written L = {R E R^2| R = AP + (1-A)Q for A between 0 and 1} note: R E R^2 means that the vector is anywhere in the 2D plane. Consider now the triangle T formed by P, Q, and the origin. Write similar expression as the one above for all the points, especially including the interior of T.