If {$v_i$} is a basis of non-degenerate quadratic space ($V,B$) (finite),
prove that there exists another basis {$w_i$} such that
$$B(v_i,w_j)=1 (i=j)$$ $$or 0(i \neq j)$$
Sorry for the ugly text styling, I don't know how to use them very well.
I am stuck from the very beginning, can anyone help me?