# Due Friday, September 11th

Due Friday:

• To Know:  I have lowered the threshold to 36 daily tasks out of 45 to count as 100%.  See the Grading page.  This is because I know life happens, so if you have to quarantine, are ill, have religious observances, etc., this should cover it.
• To Know:  Until Friday night, you can attempt this week’s iteration of Sets I and Sets III written assessments.  If you haven’t yet earned one or both badges, please give them a try.  Sets I is on its third iteration, so pull out all the stops before you try it, to make sure you earn it: study up on that topic (review zoom videos, study textbook 1.1 and 1.3 with exercises, and contact me for clarifications on anything you got wrong on the earlier assessments.  I’d rather talk to you personally about your errors than hand out solutions, so we can catch any misconceptions; try me on discord).
• To Know:  I will soon post the next proof quiz (this one is due Sept 9).  There will be one due each Monday, ideally.
• To Do:  If you haven’t yet, I’d appreciate your anonymous feedback on the course so far.
• To Do:
• Recall that in class last time we were gearing up to prove that if n is odd, then n^2 is odd.  If you need to, review the video from class.
• Write n = 2k+1.  Square both sides and expand on the right.
• Watch this video I made.
• Without having the video evenness proof visible, write your own proof of the oddness theorem (If n is an odd integer, then n-squared is odd.)  You’re aiming for the ability to transfer what you learned without having the structure of the proof available as a crutch.  If you can’t, then watch the video again, then put it totally away again, and then try the proof again.
• Hand our proof into the canvas dropbox.
• With what time remains, or when you have time in the near future, you should read textbook Section 4.2 and the first three pages of 4.3 (at least).  Don’t do this until after you’ve done the proof above (as it discusses the proof!).  Then try exercises from Section 1.1 C and D on set builder notation.