∫(0→a) xƒ''(x - a) dx
= ∫(0→a) x d[ƒ'(x - a)]
= xƒ'(x - a) |(0→a) - ∫(0→a) ƒ'(x - a) dx
= aƒ'(0) - ƒ(x - a) |(0→a)
= aƒ'(0) - ƒ(0) + ƒ(- a),ƒ'(0) =
= a - a + ƒ(a)
= ƒ(a)
∫(0→a) xƒ''(x - a) dx
= ∫(0→a) x d[ƒ'(x - a)]
= xƒ'(x - a) |(0→a) - ∫(0→a) ƒ'(x - a) dx
= aƒ'(0) - ƒ(x - a) |(0→a)
= aƒ'(0) - ƒ(0) + ƒ(- a),ƒ'(0) =
= a - a + ƒ(a)
= ƒ(a)