∫(x-a)(b-x)dx=∫[-x^2+(b-a)x-ab]dx=-1/3*x^3+1/2*(b-a)*x^2-ab*x在(a,b)上求值得积分为=5/6*a^3+1/6*b^3-3/2*ab^2+1/2*a^2*b
