I would like to evaluate two more derivatives. They are $ \frac{dx}{d\phi}\big|_{\phi^+} $ and $ \frac{dz}{d\theta}\big|_{\theta^+} $ given $x = r \sin\theta\cos\phi$ […]

In this post, I derive the so-called product rule that is taught in a Calculus course. The product rule enables one to […]