答：设x=sint∫ x³ /√(1-x²) dx=∫ sin³t /cost d(sint)=∫ sin³t dt=∫ sint(1-cos²t ) dt=∫ (cos²t-1) d(cost)=(1/3)cos³t -cost +C=(1/3)(1-x²)√(1-x²)-√(1-x&...