prove that if|.|is a vector norm, and if we define|x|'=a .|x|(a is a positive constant), then|.|'is a norm.

* numerical analysis

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- Dec 1st 2012, 05:44 AMmshounumerical analysis (norm)
prove that if

**|.|**is a vector norm, and if we define**|x|'=a .|x|**(a is a positive constant), then**|.|'**is a norm.

* numerical analysis - Dec 1st 2012, 06:11 AMRBowmanRe: numerical analysis (norm)
There are three properties needed to be checked to make |.|' a vector norm.

(I) |cv|' = a|cv| = a(c|v|) = c(a|v|) = c|v|'.

(II) |v + w|' = a|v + w| <= a(|v| + |w|) = a|v| + a|w| = |v|' + |w|'.

(III) if |v|' = 0, then a|v| = 0,|v| = 0, and v = 0 [this last 0, the zero vector.]

In each case, the norm properties of |.| have been used to show that |.|' satisfy them as well.

Hope this helps. - Dec 1st 2012, 06:38 AMmshouRe: numerical analysis (norm)
thanks : )

yea it works.