I need to show one of the two following equivalent results. If true, it must be a simple proof but I do not seem to be able to make it work. Thank you in advance.
1) Consider a continuous symmetric bilinear form $B$ on a Hilbert space. Let P be a closed subspace of that Hilbert space over which the form is coercive, i.e, there exists $\alpha\in \mathbb{R}$ such that $B(p,p)\geq \alpha \| p \|^2$ for all $p\in P$. Take the union of $P$ with a one dimensional subspace generated by an element which we will call $y$. Let say $B(y,y)>0$. Then then I need to show that $B$ is also coercive on the new subspace.
Another result that would do the trick for me goes as follows:
2) Consider a continuous symmetric bilinear $B$ form on a Hilbert space. If $v_n, {n\in \mathbb{Z}}$ is a basis of the Hilbert space and there exists a $\alpha$ such that $B(v_n,v_n)\geq \alpha \| v_n \|^2$ for all $v_n$, then $B$ is coercive, i,e, there exists $\alpha'\in \mathbb{R}$ such that $B(h,h)\geq \alpha' \| h \|^2$ for any $h$ in the Hilbert space.