Dear Wentao,

 Please consult

https://sites.math.rutgers.edu/~zeilberg/Hist21/q2S.pdf

for the full solutions.

You got 5 points (out of 10). Good job!


#1, #3, #4 is right. Next time you have to explain #4, but this time I did not take points off for that.


You are welcome to come to my office hours (both on-line and in-person)


 Best wishes,

   Dr. Z.