Find the coordinates of the point which divides the line segment joining the points (1,−3) and (−3,9) in the ratio 1:3 internally.
Using the section formula, if a point (x,y) divides the line joining the
points (x1,y1) and (x2,y2) in the
ratio m:n internally, then (x,y)≡(mx2+nx1m+n,my2+ny1m+n)
Substituting (x1,y1)=(1,−3) and (x2,y2)=(−3,9) and m=1,n=3 in the section formula, we get
the point (1(−3)+3(1)1+3,1(9)+3(−3)1+3)=(0,0)