Convex function of demand, convexdistribution of price and an optimal model for coexistence of multi-prices are established.
建立了商品销售中的凸需求函数，凸分布和多种价格并存的优化模型。
2
Second, a convexdistribution model for the price is proposed. The formulae are given respectively for the expectation price, the variance of the price and the income.
其次，提出了价格的凸分布模型，并给出了期望价格，价格的方差和期望收益的计算公式。
3
The calculation results show that the pressure distribution shape is a convex parabola and the increase of the radial taper of the seal face can decrease the friction coefficient.