⟨f, g⟩ = ∫[0, 1] f(x)g(x)̅ dx.
In this chapter, we will discuss the fundamental concepts of functional analysis, including vector spaces, linear operators, and inner product spaces. kreyszig functional analysis solutions chapter 2
Then (X, ⟨., .⟩) is an inner product space. ⟨f, g⟩ = ∫[0, 1] f(x)g(x)̅ dx