# Quiz 4

Common Mistakes:

• (Section F) Some students didn’t factor out the common factors in their answers. Couple of them mistakenly thought that factoring out common factor is the same as throwing them away.
• (Section G) One of most common wrong arguments for the first problem is by saying that the fraction is of type 0 over 0, so certainly it is undetermined or undefined. This is not true. For instance we know that $\frac{\sin x}{x}$ is of type 0 over 0 as $x\to 0$, and its limit exists. Some students use l’Hôpital rule to solve the problem, which is good.