Suppose that c is the line segment from (a, b) to (c, d). (a) Show that: xdy - ydx = ad - bc Briefly describe what this integral represents geometrically. Hint: Think back to linear algebra. What do determinants measure? (b) Suppose that a polygon P has vertices {(xi, yi) }" in counter-clockwise order. Use Green's theorem to show that P has area: = [(142 - 291) + (243 -2342) + + (Un-1Un - Knyn-1) + (any1 - 21yn)]