求和:1/k(k+1)(k+2)

问题描述:

求和:1/k(k+1)(k+2)

a/k+b/(k+1)+c/k+2=1/k(k+1)(k+2)列方程求a、b、c即得答案
a+b+c=0
3a+2b+c=0
2a=1
求的a=1/2,b=-1,c=1/2