因为分母是√1-4x^2所以设 x=cost/2dx=-sint/2 *dt则√1-4x^2=sint所以原式化为∫(cost/2-1)/sint *(-sint/2 *dt)=1/2∫(1-cost/2)dt=1/2∫dt -1/4 * ∫costdt=1/2*t-1/4∫dsint=t/2-sint/4因为x=cost/2t=arccos(2x)...