若a+b+c=0则a(1/b+1/c)+b(1/c+1/a)+c(1/a+1/b)的值为?
问题描述:
若a+b+c=0则a(1/b+1/c)+b(1/c+1/a)+c(1/a+1/b)的值为?
答
∵a+b+c=0∴a+b=-c,或a+c=-b,或b+c=-aa(1/b+1/c)+b(1/c+1/a)+c(1/a+1/b)=a/b+a/c+b/c+b/a+c/a+c/b=(a/b+c/b)+(a/c+b/c)+(b/a+c/a)=(a+c)/b+(a+b)/c+(b+c)/a=-b/b+(-c/c)+(-a/a)=-1-1-1=-3.不懂的欢迎追问,...-1-1-1怎么来的-b/b=-1-c/c=-1-a/a=-1所以,-1-1-1=-3不懂的欢迎追问,如有帮助请采纳,谢谢!