Reciprocal Rule

[@luxyivan393]

Your videos are soooo helpful. Thank you so much ❤️

[@PhysicalChemistry]

Great, I'm glad you like them

[@nikhilnagaria2672]

Isn't this just a special case of Chain Rule where f(x) = x (regd. previous video) as dx/dx = 1?

[@PhysicalChemistry]

Yes, great point. As you point out, dx/dx = 1 so, using the chain rule, dx/dx = ∂x/∂y ∂y/∂x = 1 which is just the reciprocal rule. If this seems natural to you, then you're ahead of things, and only have to remember the chain rule, and not the extra reciprocal rule as well. But we run across "upside down" derivatives all the time, so it's also useful to be able to refer to this rule (reciprocal rule) by name.