# Summary Notes for Differentiation and its Application – O Level Add Math There’s quite a number of concepts tested for differentiation and its application. In fact, this is the largest topic in O Level Additional Mathematics. We talked about what’s in the syllabus for differentiation and its in this post here. In this post, let’s summarize the concepts from these topics of differentiation.

## Differentiation Formula

These are the basic formulae that you should know for O Level Add Math differentiation. As they are not in the formula booklet, make use you remember them!

## Chain rule, Product Rule and Quotient Rule in Differentiation

### Chain Rule

• Use the chain rule if you only have one group of expression with a power

, where u is an expression in terms of x.

### Product Rule

• When you have 2 groups of expressions (e.g. u and v) multiplied with each other, use product rule for differentiation.
• Product rule formula:

where u and v are expressions in terms of x

### Quotient Rule

• When you have 1 expression divided by another, use quotient rule for differentiation. where u and v are expressions in terms of x.
• You can also change the power of the denominator to a negative one, and use product rule for differentiation. See example below:

where u and v are expressions in terms of x

## First Derivative, Second Derivative, and so on

Assuming that we have a function y = f(x), when we differentiate it, we are finding the first derivative of y or dy/dx.

• First derivative = dy/dx
• Second derivative (d2y/ dx2)
• When you differentiate the first derivative, you get the second derivative or d2y/ dx2
• third derivative (d3y/ dx3)
• When you differentiate the second derivative, you get the third derivative or d3y/ dx3

## Increasing and decreasing functions and Differentiation

• Increasing functions: dy/dx > 0
• Decreasing functions: dy/dx < 0

## Tangents and Normals

• Gradient of tangent at P = dy/dx at the point P

## Rate of change and chain rule

• Example of chain rule: dy/dt = (dy/dx)(dx/dt)

## Stationary Points / Maximum ,  Minimum and Point of Inflexion

• Maximum points, minimum points and points of inflexion are stationary points. At these points, dy/dx = 0.
• Maximum point:
• second derivative < 0
• Minimum point:
• second derivative > 0
• Point of inflexion:
• second derivative =  0 (there is no change in sign of the first derivative slightly before or slightly after that point of inflexion)

Mathematics is all about applying and being able to do questions. Apart from knowing these notes and formulae, you must also be familiar with how to apply them to the questions. The nice thing about Additional Mathematics is the questions are quite standard.

In my course on differentiation and its application, I go into detail not only the concepts but how to apply them. We also go through many questions together step-by-step, so that students finish the course equipped with the skills needed to tackle their test and exam questions on differentiation and its application with confidence. You can purchase the course instantly on Udemy, and watch and learn instantly. Get our course on differentiation here.