Question

已知 （b+c)/a - (a+c)/b - (a+b)/c ,求c/(a+b)的值

Answer 1

当a+b+c=0时,a+b=-c,

则c/(a+b)＝-1

当a+b+c≠0时

设(b+c)/a = (a+c)/b = (a+b)/c=x

b+c=ax a+c=bx a+b=cx

三式相加 2(a+b+c)=(a+b+c)x

x=2

所以 a+b=2c

所以c/(a+b)＝c/(2c)=1/2