Question

I'm completly lost on problem set one Q 1A -4

Answer 1

You mean the question about even and odd functions? That's not part of the assignment. During the course, Professor Jerison occasionally refers to odd and even functions but the concept isn't explained in the course. I note that there's a typo in part b of the question, where the numerator of the second fraction should have a minus sign in place of the plus sign. Is that what has you confused?

Answer 2

Odd / Even functions are mentioned in session 5, clip 3 (Infinite Discontinuities). Essentially a function is even if it is symmetric with respect to the y axis, expressed as f(x) = f(-x). A function is even if it is symmetric with respect to the origin 0,0 (not the x-axis), expressed as f(-x) = -f(x). This is a diagonal symmetry from compass SW to NE or NW to SE.