题目有错,估计应为:
(x+5)/[(x+1)(x+3) ]=A/(x+1) +B/ (x+3)
同乘以(x+1)(x+3):
x+5 =A(x+3)+B(x+1)=(A+B)x+3A+B
A+B=1
3A+B=5
A=2 B=-1
也可能是:
(x+5)/[(x+1)(x-5) ]=A/(x+1) +B/ (x-5)
可与上述解法类似.
题目有错,估计应为:
(x+5)/[(x+1)(x+3) ]=A/(x+1) +B/ (x+3)
同乘以(x+1)(x+3):
x+5 =A(x+3)+B(x+1)=(A+B)x+3A+B
A+B=1
3A+B=5
A=2 B=-1
也可能是:
(x+5)/[(x+1)(x-5) ]=A/(x+1) +B/ (x-5)
可与上述解法类似.