Found in 1 comment on Hacker News
todd8 · 2016-12-08 · Original thread
For those interested in math and particularly in learning how to attack challenging (definite) integrals, I can recommend this book by Paul Nahin: Inside Interesting Integrals [1]. It's well reviewed on Amazon and I enjoyed the writing.

[1] https://www.amazon.com/gp/product/1493912763/ref=oh_aui_sear...