I'm not sure how Borges was influence and what he is trying to say in Kafka and his precursors.

Well Borges was a big reader and he is influenced by a lot of philosophers who were European so I would suggest in researching some of those who influenced him, In his predecessors he is trying to bring into question Identity as a question. Whether we are each unique or if we aim to write like our predecessor or model our works. But he explains that we don't know until after it is written that predecessors are found within the work and not determined by the author.

I still don't remember how to figure out a way to remember the unit circle. Is there an easier way to remember it.

To begin you may want to think about the circles being divided by 12 and the entirety of the circle being 2pi which makes it easier to remember where the values go. And then you can remember just 1/4 of the circle in the first quadrant and then you can use those numbers to determine the values of the other.

I still don't understand how to figure out what to do first according to the order of operations. When there are parenthesis and an exponent why does it matter if the exponent is inside or outside of the parenthesis?

Well an acronym that you can use to remember what to do is PEMDAS which stands for parenthesis, exponent, multiplication/division, and addition/subtraction. So when you're looking at an equation you take into account everything in the parenthesis when considering exponents. For example if it is (-2)^2 you would square -2 and if you have -(2)^2 you would only square 2 and then multiply the result by negative 1.