hi,

given two vectors:

$\displaystyle v_1=\left[\begin{array}{cc}1\\1\\1\\1\end{array}\right]$

and

$\displaystyle v_2=\left[\begin{array}{cc}1\\2\\3\\4\end{array}\right]$

i need to come up with two more vectors (eg U_1 and U_2) which when in a set with the first two create a basis for R^4. i tried using like a1,b1,c1,d1 for each u_1 and U_2 and getting it into REF but i had no joy. apparently according to my friend you should be able just to guess the vectors which satisfy this.

thanks,