I was searching through the internet for an equation that defines the path followed by a racing line, when I came across the following formula on StackExchange posted by another user as a reply for another user. However, I could not understand what kind of maths is being used in the proof submitted by this user:
I created this account, but couldn't comment on the user's proof, so I decided to post it as a question. I would appreciate it if someone was able to explain to me just what kind of maths was used to solve the problem.
I understand that it involves trigonometry, but I can't seem to figure out exactly how he used it to solve this problem and how he applied trigonometry to solve it, as I don't think I have advanced that far in maths.
I am not sure how I am supposed to apply trigonometry here because I honestly cannot understand how each he (or she) transitions from the first equation to the second and then to the third.