I have corrected a few mistakes in the assignment solutions, as follows (a big thank you to Mengmeng Shang for pointing them out to me!):--

-- In 3b), the final answer should not include an x. The x should be entirely replaced by the limits. (Note though that in this case I have not said that k was an integer, so we can't simplify further.)
-- In 5b), the second matrix should have had a π^2 instead of a π.

In addition, I corrected the following more minor errors:

-- Clarified some of the logic in 3e)-g). (These solutions are worth reviewing.)
-- In 4b) and 4c), one should say "R is represented by ..." rather than "R = ...".

Please let me know if you see any other errors or have any other questions about the homework solutions. See you all this afternoon!

Nathan