Question

Mutlivariable calculus - explanation of Kepler's law using vectors:
((Δr/Δt). Δs) tends to zero, as Δt tends to zero.
Can anyone please explain this, as it looks like Δr tends to zero, before Δs does.
Please explain how to look at such expressions. Thanks.

Answer 1

Delta r/Delta t tends to a FINITE limit and when this is multiplied by Delta s which is necessarily tending to zero the product must tend to zero

Answer 2

Thanks!