若2/x^-1=（A/x-1）+（B/x+1）,求A、B值
问题描述：
若2/x^-1=（A/x-1）+（B/x+1）,求A、B值
答
解
2/(x²-1)=A/(x-1)+B/(x+1)——这个吧
2/(x²-1)=A(x+1)/(x²-1)+B(x-1)/(x²-1)
=(Ax+A+Bx-B)/(x²-1)
∴(A+B)=0
A-B=2
∴A=1,B=-1Ϊʲô��(A+B)=0A-B=2����(Ax+A+Bx-B)/(x²-1)=2/(x²-1)��(A+B)x+(A-B)=2��A+B=0��A-B=2