>>498
>= -(a/2)∫[α,β](x-α)^2dx
http://www.wolframalpha.com/input/?i=-%28a%2F2%29*integrate%28%28x-%CE%B1%29%5E2%2C%7Bx%2C%CE%B1%2C%CE%B2%7D%29

妙なルアーだな