这样
最后一步你算出来
令x=sint,则√(1-x²)=cost,dx=costdt
∴原式=∫ cost/(sint+cost) dt
=(1/2)∫[(cost+sint)+(cost-sint)]/(sint+cost)] dt
=(1/2)∫ dt + (1/2)∫(cost-sint)/(sint+cost) dt
=t/2 + (1/2)∫d(sint+cost)/(sinx+cosx)
=(1/2)(t+ln|sint+cost|) + C
=(1/2)(arcsinx+ln|x+√(1-x²)|)+C
C为任意常数