Euclidean Distance

Definition:

• Distance of 2 vectors in Euclidean way of measuring distance
  • $d(x,y)=||x-y|{|}_2$
• $||x+y|{|}_2^2=(x+y{)}^T(x+y)=||x|{|}_2^2+||y|{|}_2^2+2x^{T}y$
• We also have triangla inequality: $d(x+y)\le d(x)+d(y)$