nonlinear non-separable problem

例句：

1. 1. The system is nonlinear, meaning that small changes in one variable can have a big effect on the other variables.
   这个系统是非线性的，意味着一个变量的小变化会对另一个变量产生很大的影响。
2. 2.In physics, a nonlinear equation describes how the state of a system changes with respect to the values of its variables.
   在物理学中，一个非线性方程描述了系统的状态如何随着其变量的值而变化。
3. 3. Nonlinear systems are often used in engineering because they can exhibit complex behaviors that cannot be predicted by linear models.
   非线性系统在工程中经常被使用，因为它们可以表现出线性模型无法预测的复杂行为。