Why does the erf function show up in the solution to this 2nd order differential equation?
(y'')^-1 = y
(y'')^-1 = y
In my last physics exam I needed the initial position P of the car. At first glance I thought it was pi because it was right where pi would be if you divided the circle like any other, but then I noticed the labeled axises and my common sense kicked in:
"Hey, the x axis is the horizontal axis and the y axis is the vertical axis, they probably want me to rotate the axises so they're in their proper positions then start counting from the x axis, and they labeled them this way to confuse me and I was aware enough to notice it"
Thus I considered the initial position of the car to be pi/2 and I went on to find the movement equations of the car through integration.
Later on, during the exam revision, I noticed I had this problem with a big red cross over it and I asked the professor why, to which he told me: "you considered the initial position of the car as pi/2 when it was pi, the rest of the problem is wrong because of that"
We had a long and exhausting discussion as to why and why not my thought process was correct, which ultimately led us nowhere and left my exam score unchanged.
After making peace that we all simply guess wrong sometimes, I come to you now /sci/, was my thought process correct? was I wrong? was I a victim of a bullshit arbitrary decision to NOT consider the deliberately labeled axises to find the right answer?
