Uploaded April 2026 | Updated September 2026, 2 weeks ago

---

This is a Calculus 3 tutorial on how to prove that a multivariable function is differentiable everywhere using the definition.
----------------------
I help students master the basics of calculus. You can show your support and help me create even better content by becoming a patron on Patreon 👉 patreon.com/blackpenredpen
Get the coolest math shirts from my Amazon store 👉 amzn.to/3qBeuw6
----------------------
Want more practice? Get my calculus practice quizzes on Patreon!
Calculus 1 👉 patreon.com/collection/1703815
Calculus 2 👉 patreon.com/collection/1716951
----------------------
#calculus #bprpcaluclus #mathtutorials #math