The problem session began with a discussion of quiz5.
The sample and sample solutions were explained. Then quiz5
was discussed in more detail, especially the changes from the sample and the 
requirements to solve the problems. Problem 3 on quiz 5 is extra credit. If
you made a print last week, then please print again, to get correct references.
Problems 1 and 2 remain the same as the previous week (source from 2014).


The discussion of quiz 6 was complete. Both the RC network problem and the
distillation column problem. 

RC NETWORK. Explained were the three equations for the currents I1, I2, I3, and 
why 2 redundant equations were dropped from the original 5x5 system of equations. 
A derivation from KCL and KVL is not required to solve the problem, but it is 
required in order to understand the problem. Also discussed was the RREF step 
and the solution step.

In the blackboard photos, you can find an explanation of the phrase "70 kg-mol/min" 
although a complete explanation is a visit to an elementary chemistry textbook. 
Discussed for the distillation column problem was the derivation of the 4 linear 
equations for variables.

The session ended with a discussion of HW5 problems. These have blackboard photos:

   3.4-29, 3.4-30, 3.4-36

A common problem with the Four Rules (textbook's Method of Elimination) was unearthed. Many rules
for solving equations are not the fundamental operations called combo, swap, mult. For example, the
operation(  2) Row1 + (-1) Row2 -->  Row2  breaks down into combo(1,2,2) plus mult(2,-1). For determinants,
the Four Rules apply only to combo, swap, mult. A swap multiplies the answer by (-1). A mult divides the
answer by the multiplier (same as multiply the answer by 1/m).