Strategy and Method for Solving Problems

Depending on the problem (referring, mainly, to this chapter), some steps can be omitted, e.g., the graphical representation. 

Although some of the proposed steps are self-explanatory, an explanation of each step is included as follows. 

This first step is critical. Sometimes with long statements you get confused. Although you understand the question, it might be hard to formulate the equations. As Imig as you have identified your unknowns, and coded accordingly, a good idea is to go phrase by phrase translating them into mathematical expressions. 

Normally a good scheme or graphical representation lets us have a clear picture of the problem. In addition, we need to identify all the unknowns and then assign each one an adequate code to define each variable. For example, if in a given problem an airplane s speed is unknown, an appropriate coding to define the speed of the airplane could be Va- 

Once all variables have been identified and defined, it is necessary to determine which equations can be formulated. To pose the problem, the number of variables should be equal to the number of equations that can be formulated. In Chap. 7, when we deal with problems related to material balance, we will analyze and extend the concept of degrees of freedom (DF. For now DF is defined as follows DF = Number of variables — Number of equations. 

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