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我们知道,某些实际问题中的数量关系能够用代数式表示;反过来,一个代数式也就表示某个具体问题中的数量关系.但是,同样一个代数式却可以表示不同的实际意义,往往在一系列问题中通用,成了计算公式,代数式2/(1/a+1/b)就是其中一个,现举几例.1表示平均速度例1小华往返于甲、乙两地之间,去时的速度为a km/h,回程时速度为b km/h,求小华全程的平均速度.解设甲、乙两地间的路程为单位1,
We know that the quantitative relations in some practical problems can be expressed algebraically; in turn, an algebraic equation also means the quantitative relation in a specific problem, but the same algebraic expression can mean different meanings, often in a series The problem is universal, has become the formula, the algebra 2 / (1 / a + 1 / b) is one of them, to give a few examples .1 said the average speed of 1 Xiaohua to and from between A and B, to go The speed of a km / h, back to the speed of b km / h, find the average speed of Xiaohua throughout the solution set A, B two distance between the unit 1,