1.函数与实际问题例l今年我省部分地区遭遇干早,为鼓励市民节约用水,我市自来水公司按分段收费标准收费,图1反映的是每月收取水费y(元)与用水量x(吨)之间的函数关系。(1)小聪家五月份用水7吨,应交水费元;(2)按上述分段收费标准,小聪家三、四月份分别交水费29元和19.8元,问四月份比三月份节约用水多少吨。图1解析:(1)从函数图像可知,当0≤x≤10时,y与x之间 1. Functions and practical problems Example l In some areas of our province, this year was dry and early. To encourage citizens to save water, the city’s water companies charge according to the sectional fees. Figure 1 reflects the monthly water fee y (yuan) and water consumption. Quantity x (tons) as a function of the relationship. (1) Xiao Cong’s home has 7 tons of water in May and should pay water bills; (2) According to the above-mentioned subsection charges, Xiao Congjia paid 29 yuan and 19.8 yuan for water bills in March and April respectively. How many tons of water are saved in the month. Figure 1 Analysis: (1) From the function image we can see that when 0 ≤ x ≤ 10, between y and x