The electric field and capacitance of a confocal elliptic capacitor are calculated by the inverse hyperbolic cosine analytic function, and discussion on them is performed. 利用解析函数的性质,通过反双曲余弦计算出了由共焦点椭圆导体柱面组成的电容器内电场和单位长度的电容,并对结果作了进一步讨论。
Three common mathematic models are always employed to predict the growth of regional or urban population, including exponential function ( Malthus model), inverse hyperbolic function ( Keyfitz model), and logistic function ( Verhulst model). 预测人口增长的数学模型通常采用3种函数,即指数函数、Logistic函数和双曲函数。