∫(√x+1-1/√x+1-1)dx
令x+1=t2,则=t2-1,dx=2tdt ∫[(√x+1-1)/(√x+1+1)]dx=∫[(t-1)/(t+1)]2tdt =2∫[(t2-t)/(t+1)]dt=2∫[t-2+2/(t+1)]dt =2∫tdt+4∫dt+4∫[1/(t+1)]dt =t2-4t+4ln|t+1|+C =(x+1)-4√x+1+41n(√x+1)+C.
∫(√x+1-1/√x+1-1)dx
令x+1=t2,则=t2-1,dx=2tdt ∫[(√x+1-1)/(√x+1+1)]dx=∫[(t-1)/(t+1)]2tdt =2∫[(t2-t)/(t+1)]dt=2∫[t-2+2/(t+1)]dt =2∫tdt+4∫dt+4∫[1/(t+1)]dt =t2-4t+4ln|t+1|+C =(x+1)-4√x+1+41n(√x+1)+C.