However , this system can also be solved exactly to yield the following generalized expressions :
If the concentration at the time t = 0 is different from above , the simplifications above are invalid , and a system of differential equations must be solved .
This system can also be solved exactly to yield the following generalized expressions :
If the concentration at the time t = 0 is different from above , the simplifications above are invalid , and a system of differential equations must be solved .