Distance between parallel hyperplanes. Consider two hyperplanes.  H_1 = {x epsilon R^n|a^T x = b}, H_2 = {y epsilon R^n|a^T y = c}, where a is a nonzero n-vector, and b and c are scalars. The hyperplanes are parallel because they have the same coefficient vectors a. The distance between the hyperplanes is defined as  d = min ||x - y||  x epsilon H_1  y epsilon H_2  Which of the following three expressions for d is correct? Explain your answer.  d = |b - c|  d = |b - c|/||a||  d = |b - c|/||a||^2.
option (b)
 proof let
  
  Therefore the intersection point is     x2=x1+a(bbcccc)/aTax2=x1+a(bc)/aTa. The distance between these two points is the distance between the hyperplanes:
  
       |  |                aT(x1+at)=ct=(cbcaTx1)/aTa=(bc)/aTaaT(x1+at)=bt=(baTx1)/aTa=(bc)/aTa
   Therefore the intersection point is         x2=x1+a(bbcccc)/aTax2=x1+a(bc)/aTa.  The distance between these two points is the distance between the  hyperplanes:          x1x2=|bccc|aTaa=|bccc|a |