Paper 4, Section I, F

Linear Algebra | Part IB, 2010

Define the notion of an inner product on a finite-dimensional real vector space VV, and the notion of a self-adjoint linear map α:V→V\alpha: V \rightarrow V.

Suppose that VV is the space of real polynomials of degree at most nn in a variable tt. Show that

⟨f,g⟩=∫−11f(t)g(t)dt\langle f, g\rangle=\int_{-1}^{1} f(t) g(t) d t

is an inner product on VV, and that the map α:V→V\alpha: V \rightarrow V :

α(f)(t)=(1−t2)f′′(t)−2tf′(t)\alpha(f)(t)=\left(1-t^{2}\right) f^{\prime \prime}(t)-2 t f^{\prime}(t)

is self-adjoint.

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