Unit R Concept 1 Student Problem

What is this problem about?

These images show a problem from Unit R Concept 1, the  degree is 315. The top 2 images portrays the difference equation and the bottom image shows the sum formula. 

What does the viewer need to pay close attention to ?

The viewer needs to pay closes attention to see whether the ordered pairs do correspond to the degrees that were added because if they aren't they won't give you the same answers for the sum and difference problem. That leads me to another key point both the sum and difference problem have the same answer,  this is supposed to occur when solving the same problem both ways. Next, we need to pay attention to the Positive and Negative signs in the problem, we need to make sure we include them in the equations when solving. Lastly make sure you write down the correct formula because I wrote down the wrong formula at first when trying to solve the difference of tan and I noticed the answers didn't match up  with  he sum equations then I fixed my mistake. Well,  Thank You for taking the time to view my pictures.