g Let x=(5,2,4)Tx=(5,2,4)T and y=(3,3,2)Ty=(3,3,2)T. Compute ‖x−y‖1,‖x−y‖2‖x−y‖1,‖x−y‖2, and ‖x−y‖[infinity]‖x−y‖[infinity]. Under which norm are the two vectors closest together? Under which norm are they farthest apart?

Respuesta :

By definition of the [tex]\ell_p[/tex] norm,

[tex]\|x-y\|_1 = \displaystyle \sum_{i=1}^3 |x_i-y_i| = |5-3|+|2-3|+|4-2| = \boxed{5}[/tex]

[tex]\|x-y\|_2 = \displaystyle \left(\sum_{i=1}^3 |x_i-y_i|^2\right)^{\frac12}= \sqrt{|5-3|^2+|2-3|^2+|4-2|^2}= \sqrt9= \boxed{3}[/tex]

[tex]\|x-y\|_\infty = \max\limits_{i} |x_i-y_i| = \max\left\{|5-3|,|2-3|,|4-2|\right\}=\boxed{2}[/tex]

and so x and y are closest together with p = infinity and furthest apart with p = 1.