## henpen Group Title $y^2=2px$ $\Rightarrow 2ydy=2pdx$ How is this achieved at? I've always gone with calculating $2y\frac{dy}{dx}=2p$ and multiplying both sides by dx. But I know that's heresy. What's the official story as to how it's arrived at? one year ago one year ago

1. henpen Group Title

I've always found it odd how it seems plucked out of thin air

here is a link this is called differentials chew on it

3. henpen Group Title

Oh differentials- I wasn't thinking!