已知((x+2)(x-2))分之(2x+1)=((x+2)分之a)+((x-2)分之b)(a、b为常数求:a、b值
问题描述:
已知((x+2)(x-2))分之(2x+1)=((x+2)分之a)+((x-2)分之b)(a、b为常数求:a、b值
答
(2x+1)/(x+2)(x-2)=A/(x+2)+B/(x-2)
A/(x+2)+B/(x-2)
=A(X-2)/(X+2)(X-2) +B(X+2)/(X+2)(X-2)
=[A(x-2)+b(x+2)]/(x+2)(x-2)
所以2x+1=A(X-2)+B(X+2)=(A+B)x-2(A-B)
所以A+B=2,-2(A-B)=1
解得:A=3/4,B=5/4
不懂的欢迎追问,