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经济发展,生活实践,为数学应用题的产生提供了有利条件.精致的好题不胜枚举,一些精心加工后的活题不仅立意高、情境新、设问巧,而且有极其浓厚的时代气息,以下几例,与读者同赏共析.[例1]一条河宽1km,两岸平行的直线上各有一城市A与B,A、B的直线距离为4km,现在要铺设一条电缆连接A与B,已知地下电缆每公里需2万元,水下电缆每公里需4万元,如何放设才能使费用最少?
Economic development, life practice, for the production of math problems provide favorable conditions.Exquisite to go through numerous questions, some elaborately processed topics not only high conception, new situations, set Qiaoqiao, but also has a very strong flavor of the times Example 1 A river with a width of 1km and a straight line parallel to each other on both sides of a city has a straight line distance of 4km between A and B, A and B, and now it is necessary to lay down a cable connecting A and B, known underground cable 20,000 yuan per kilometer, underwater cable need 40,000 yuan per kilometer, how to put in order to make the least cost?