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## Main Question or Discussion Point

How do I prove that the parity operator Af(x) = f(-x) commutes with the second derivative operator. I am tempted to write:

A∂^2f(x)/∂x^2 = ∂^2f(-x)/∂(-x)^2 = ∂^2f(-x)/∂x^2 = ∂^2Af(x)/∂x^2

But that looks to be abuse of notation..

A∂^2f(x)/∂x^2 = ∂^2f(-x)/∂(-x)^2 = ∂^2f(-x)/∂x^2 = ∂^2Af(x)/∂x^2

But that looks to be abuse of notation..