Another Lesson Learned

Today we went over alot of examples similar to the questions found on exercise 4. I learned that when you factor a binomial expression (Ex x2+2x+1=0) there is the possibility that you could end up with an answer that looks like costheta=3 or anything that will cause a calculation error. In an situation like that you will completely ignore that part of the question, therefor the complete answer will solely come from the other half of the question. this concept in my head is similar to non-permissible values; answers that fit the description and seem to work out, but only cause you grief and despair!