title: Manipulation the Euclidean norm in such a way to make a new vector
body: <p>Suppose that the Euclidean norm of a vector (V) is computed (as A) then this norm is changed (as B). Is it any way to modify the vector (V) in such way that its norm become B ?
  For example:</p>
  
  <pre><code>A=[7 3 1];
  n1=norm(A);
  n2=n1*0.2;
  </code></pre>
  
  <p>Find a new vector that its norm become n2 ?
  Thanks.</p>