linear hyperbolic equation of higher order

例句：

1. 1. Thepath is linear and easy to follow.
   这条路线是直线的，很容易跟随。
2. 2. Thedata is linearly proportional to the input.
   数据与输入成正比例关系。
3. 3. The company's growth is linearly related toits profits.
   公司的增长与其利润呈线性关系。