IB Math AA HL Nov 21 TZ0 Paper 1: Integrating Factors Are Smelly

The integrating factor question that starts at 21:30, skip to 26:20 ish lol. I also meant to say the integrating factor basically creates a Product Rule at 30:00 ish, not chain rule

[sadie]

thank you for doing the question on integrating factors. you made it seem so simple, and i think i finally understand it.

[murray]

at 1:11:06 how do you know to put k as 1 and 2 and not -1, and 1 for example? why strictly positive?

[jaybird]

why are you able to just entirely ignore the root 1-x in question 9