# Browsing category core 4

## Ask Uncle Colin: Parametric Second Derivatives

Dear Uncle Colin, I have a pair of parametric equations giving $x$ and $y$ each as a function of $t$. I'm happy with the first derivative being $\diff{y}{t} \div \diff{x}{t}$, but I struggle to find the second derivative. How would I do that? - Can't Handle An Infinitesimal Nuance Hi,

## Ask Uncle Colin: Integration rules

Dear Uncle Colin, Why can't I work out $\int \left( \ln(x) \right)^2 \dx$ using the reverse chain rule? -- Previously Acceptable, Reasonable Technique Stumbles Hello, PARTS, There are two answers to this: the first is, you can't use the reverse chain rule -- which I learned as 'function-derivative' when I

## How the Mathematical Ninja explains the Mathematical Pirate’s circle trick

"Let me see that!" commanded the Mathematical Ninja, looking at one of the Mathematical Pirate's blog posts. "That's... but that's..." "It's not wrong!" said the Mathematical Pirate, smugly. "It just works!" "But you're presenting it as magic, not as maths." The Mathematical Pirate nodded eagerly. "Lovely magic! How does it

## Blazing through the Binomial Expansion

"Where's the Mathematical Ninja?" asked the student. "He's... unavoidably detained," I said. In fact, he was playing Candy Crush Saga. But sh. "What can I help you with today?" "Well, you know the binomial expansion...?" "Intimately," I said. "Well, I got it pretty well at C2... but now we're doing

## Quotients and remainders

A few months ago, I wrote a post about replacing long division with a coefficient-matching process. That's brilliant for C2, but what happens if you're looking at a C4 question that wants a quotient and a remainder? Well, it gets a bit more complicated, that's what happens. But it's not