Let v, w be elements of a vector space and assume v does not equal 0. If v, w are linear dependent, show that there is a number x such that w=xv. Thanks for any help, Mark.
By definition of dependence $\displaystyle \alpha v + \beta w = 0\;\& \,\alpha \ne 0 \vee \beta \ne 0$.
Then if $\displaystyle \beta = 0$ then $\displaystyle \alpha v = 0$.
But $\displaystyle \alpha \ne 0\, \Rightarrow \,v = 0$ which is a contradiction.