Question

Find condition of collinerity for points (x,0) (0,y) (1,1)

Answer 1

any three points are colinear only if ,
area of ∆ form by these points = 0

area of ∆ = 1/2{ x( y -1) + 0 +1(0 -y)}
0 = 1/2{ xy - x - y}
xy - x - y = 0
x + y = xy
1/x + 1/y = 1 { after diving xy in both sides }