title: 数学作业题目在附件中,谢谢! 
desc: 题目在附件中,谢谢!
answer: 15.原式=
  ∫<0,1>[(1/3)x^2dx^2-(1/2)(x^2)^2]dx
  +∫<1,0>[(1/3)x^2d√x-(1/2)x]dx
  =∫<0,1>[(2/3)x^3-(1/2)x^4]dx
  +∫<1,0>[(1/6)x^(3/2)-(1/2)x]dx
  =∫<0,1>[-(1/2)x^4+(2/3)x^3-(1/6)x^(3/2)+(1/2)x]dx
  =[-x^5/10+x^4/6-x^(5/2)/15+x^2/4]<0,1>
  =-1/10+1/6-1/15+1/4
  =1/4,故选C.
  16.和12.重了.-1≤x-1≤1,解得0≤x≤2,故选C.
  17.√x^2-y^2>0,即x^2-y^2>0,选D.