标题: 弱问OG里的一道数学题 [打印本页] 作者: laranli 时间: 2011-10-24 13:46 标题: 弱问OG里的一道数学题 213. In an electric circuit, two resistors with resistances x and y are connected in parallel. In this case, if r is the combined resistance of these two resistors, then the reciprocal of r is equal to the sum of the reciprocals of x and y. What is r in terms of x and y ? (A) xy (B) x + y (C) 1/x + y (D)xy/x + y (E)x + y/xy 答案D。reciprocal of r is equal to the sum of the reciprocals of x and y ，个人认为此句应当理解为1/r=1/x+y；但OG似乎理解为1/r=1/x+1/y。求教各位牛牛，这句话到底表达啥意思？作者: serenana 时间: 2011-10-26 21:27
他问得是the sum of the reciprocals of x,y是两个先倒再加，而你说的那个是 the reciprocals of the sum of x,y~~我是这么理解的~~非nn一枚~~作者: shishmily 时间: 2011-10-26 22:23
他问得是the sum of the reciprocals of x,y是两个先倒再加，而你说的那个是 the reciprocals of the sum of x,y~~我是这么理解的~~非nn一枚~~