有一类关于定义新运算的习题,就是在题中规定一个新的运算法则(或概念),并按照这一新法则进行运算.现举几例说明这类问题的解法. 例1 羊和狼在一起时,狼要吃掉羊,所以关于羊及狼,我们规定一种运算,用符号△表示:羊△羊=羊;羊△狼=狼;狼△羊=狼;狼△狼=狼.以上运算的意思是:羊与羊在一起还是羊,狼与狼 There is a class of exercises for defining new calculations, which is to specify a new algorithm (or concept) in the problem, and follow this new rule. Here are a few examples to illustrate the solution to this type of problem. Example 1 Sheep and wolf When we get together, the wolf eats the sheep. So for the sheep and the wolf, we specify an operation, expressed by the symbol △: sheep △ sheep = sheep; sheep △ wolf = wolf; wolf △ sheep = wolf; wolf △ wolf = wolf. The meaning of the above operations is: sheep and sheep together or sheep, wolf and wolf