Thread: linear algebra problem

let V be a finite dimentional inner product space and let W be a subspace of V. prove that dim(W) + dim(W^)= dim(V) where W^ is a set of vectors orthogonal to W.

please help.

Since W is a subspace of an innerproduct space, we can select an orthonormal basis for W containing dim(W) vectors. Since W^ is a subspace, we can select an orthonomal basis for W^ containing dim(W^) vectors. Show that their union is a basis for the entire space.