3:15 washer method 5:00 example 1 (disk about y axis) 12:08 example 2 (disk about the x axis) 19:20 example 4 (washer about the line y=-3) 26:57 example 5 (washer about line y=-2)
I'm so glad I could help! I have another updated video with more examples that I think you’ll enjoy too: Volumes by Slicing: Disks & Washers | Solids of Revolution | FOOLPROOF EASY Method! ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-bb1YMRSmz7c.html
You integrate e^2y using u substitution . That will give you 1/2e^2y. Then you factor out that 1/2, when it multiples with the pi, it gives you pi/2@@jackhusen6
It can be so rough! The key is drawing an excellent graph! Check out the extra videos I made on this topic, they’re on the Calculus 2 Video Lectures playlist-the updated explanation is 🧑🍳💋