令x=sint dx=costdt原式=∫costdt/(sint+cost)令A=∫costdt/(sint+cost) B=∫sintdt/(sint+cost)A+B=∫(sint+cost)dt/(sint+cost)=∫dt=t+C1A-B=∫(cost-sint)dt/(sint+cost)=∫d(sint+cost)/(sint+cost)=ln|sint+co...