variable gradient

例句：

1. 1. The variable gradient is a key factor in determining the optimal design of the system.
   可变量梯度是决定系统最优设计的关键因素。
2. 2. In this study, we used a variable gradient method to solve the optimization problem.
   在这项研究中，我们使用可变量梯度方法来求解优化问题。
3. 3. The variable gradient method has been widely applied in various fields, such as engineering and economics.
   可变量梯度方法已被广泛应用于工程和经济领域。