1/A-1/B-1/A+B=0解:1/A-1/B=1/A+B(B-A)/AB=1/A+B同乘AB(A+B)B^2-A^2=AB∴(AB)^2=B^4+A^4-2A^2B^2B^4+A^4=3(AB)^2∵A^2/B^2+B^2/A^2=A^4+B^4/A^2B^2∴=3(AB)^2/(AB)^2=3答案补充对了,1/A-1/B-1/A+B=0吗?还是1/A-1/B-1/(A+B)=0,答案补充那就是这样解答了