Theorem 2.2.2. (Chain rule ) Suppose that the function is derivable at , and the function is derivable at . 定理 2.;2
When there is one harmonic source in electric power system, the harmonic component could be derivable. 摘要当电力系统中只有一个谐波源时，各点的谐波电压可以方便的求出。
The implication is that this data must be derivable from user inputs and drives the read operations on the services in a top down fashion. 这意味著该资料必须可以从用户输入派生,并以由上而下的方式驱动服务上的读取操作。
