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Differentiation: standard functions, chain, product and quotient rules

A Level Maths 9709 Paper 1 · Chapter 1.7, Differentiation · 5-minute lecture

The teaching part (1 min) is free to watch. A free account opens the whole lecture: 3 worked examples, 6 practice questions, 1 real past-paper question with the answer explained, the mistakes that lose marks, the full-marks tip, a one-card summary and a quick quiz.

What this lecture covers

  1. How fast is it changing?
  2. The standard derivatives
  3. The chain rule
Read the transcript of the teaching part

Last time

Before we start: last time, in Linked progressions, progressions in context, trigonometric terms, and sums in a range, you learned these points. Here they are again on one card. Keep them in mind, because today builds on them.

How fast is it changing?

The speedometer of a car shows how quickly the distance is changing, right now. That instant rate of change is the derivative. To differentiate quickly you need a short list of standard results, and three rules for combining them.

The standard derivatives

The derivative of x to the n is n x to the n minus one. e to the x differentiates to itself. ln x differentiates to one over x. Sine goes to cosine, and cosine goes to minus sine. Tangent goes to secant squared. Cambridge expects these in radians.

The chain rule

If y is a function of u, and u is a function of x, then dy by dx equals dy by du, times du by dx. In practice: differentiate the outer function, leave the inside alone, then multiply by the derivative of the inside. The derivative of sine of five x plus three is five cosine of five x plus three.

Chapter 1.7: Differentiation

Also for A Level Maths 9709 Paper 1

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