说明：  讨论资金积累、国民收入、与人口增长的关系. （1）若国民平均收入x与按人口平均资金积累y成正比，说明仅当总资金积累的相对增长率k大于人口的相对增长率r时，国民平均收入才是增长的. （2）作出k(x)和r(x)的示意图，分析人口激增会引起什么后果.
(Discussion of capital accumulation, income, and the relationship between population growth. (1) If the national average income per x and y is proportional to the accumulation of funds that only if the total funds accumulated in relative growth rate k of the relative growth rate than the population r when per capita income is growing. (2) to k (x) and r (x) of the diagram, analysis of population growth will cause the consequences.)