34 () posted 3 years ago by Magistra 3 years ago by Magistra +34 / -0 8 comments share 8 comments share save hide report block hide replies
From the text of picture, this comes from the Book of Q Proofs.
https://bookofqproofs.wordpress.com/
All I had to do is search Google with a good portion of the image description in quotes.
Edit: When I look at the Version 1.3 of the book, the page matches exactly.
Current version is 1.5. Have fun.