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Functions Additional Mathematics

Unveiling the power of functions: Additional Mathematics Lesson 1

The first lesson in Additional Mathematics sets the stage for an exciting journey into the world of advanced concepts. We’ll begin by demystifying the fascinating realm of functions, the building blocks of much of what you’ll encounter in this course.

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Get ready to:

  • Define what a function is: Imagine a machine that takes in an input (a number) and transforms it into an output (another number). That’s essentially what a function does! We’ll explore different ways to represent functions, such as equations, graphs, and tables.
  • Discover different types of functions: Not all functions are created equal! We’ll meet familiar faces like linear and quadratic functions, and introduce exciting newcomers like exponential and logarithmic functions. Each type has its own unique personality and quirks to discover.
  • Unleash the power of graphing: A function’s graph is its visual signature, revealing its behaviour and secrets. We’ll learn how to plot points, interpret curves, and identify key features like slopes and intercepts. Graphs become your window into the world of functions.
  • Master the language of transformations: Imagine stretching, flipping, or shifting a graph. These are called transformations, and they allow us to manipulate functions and create new ones. We’ll learn how these transformations affect the shape and behavior of functions, giving you superpowers over their visual landscapes.
  • Solve real-world problems with functions: Don’t let the abstract fool you! Functions are everywhere in the real world. We’ll use them to model population growth, calculate rocket trajectories, analyse investment trends, and solve countless other practical problems. You’ll see how mathematics connects seamlessly to the world around you.

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Definition of functions

Here’s a breakdown of what a function is, with 5 examples to illustrate its different representations:

Think of a function as a magical machine that takes in numbers (inputs), performs a specific operation on them, and spits out new numbers (outputs). Every input has exactly one unique output, ensuring order and predictability.

Here are 5 ways to represent functions, each offering a different perspective:

1. Equations:

  • Example: f(x) = 2x + 3

This equation tells us that the function f takes an input x, multiplies it by 2, and then adds 3 to produce the output.

If we input x = 4, the function outputs f(4) = 2(4) + 3 = 11.

2. Graphs:

  • Example: [Insert a graph of y = 2x + 3]

The graph of a function visually represents the relationship between inputs and outputs.

Each point on the graph corresponds to an input-output pair.

The shape of the graph reveals the function’s behaviour.

3. Tables:

  • Example:
Input (x)Output (f(x))
  • A table lists input-output pairs in an organised manner, making it easy to see specific values.

4. Verbal descriptions:

  • Example: “The function g takes a number, squares it, and then subtracts 4.”

This description explains what the function does in words, without relying on equations or graphs.

5. Real-world examples:

  • Example: The cost of a taxi ride depends on the distance travelled.

The distance is the input, and the cost is the output.

This function can be represented by an equation like C(d) = 2d + 5, where C is the cost and d is the distance.


  • Functions are fundamental in mathematics and have countless applications in science, engineering, finance, and many other fields.
  • Understanding how to represent and analyse functions is essential for solving problems and modelling real-world phenomena.
f(x) = 2x + 3. Image courtesy Mathway.

Types of functions

Different types of functions:

1. The Steady Climber: Linear Functions (y = mx + b)

  • Imagine a gentle, uphill path. That’s a linear function! Its graph forms a straight line, steadily increasing or decreasing with each step. Think about:
  • Temperature change: As time passes, the temperature might rise or fall at a constant rate, represented by a linear function.
  • Distance and speed: A car travelling at a constant speed, covers increasing distances in a linear fashion.

2. The Up-and-Down Rollercoaster: Quadratic Functions (y = ax^2 + bx + c)

  • Picture a thrilling rollercoaster ride, going up, down, and looping back. That’s a quadratic function! Its graph has a distinct U-shape, peaking or dipping before turning the other way. Imagine:
  • Profit and loss: A business might gain profits initially, then experience diminishing returns, with a quadratic curve representing its income over time.
  • Projectile motion: The path of a thrown ball, starting with an upward surge and then falling back to Earth, follows a quadratic trajectory.

3. The Rapid Climber: Exponential Functions (y = a^x)

  • Think of a rocket blasting off, its speed increasing exponentially with each second. That’s an exponential function! Its graph shoots up or down rapidly, never reaching a horizontal limit. Imagine:
  • Population growth: A rapidly growing population can be modeled by an exponential function, showing its explosive increase over time.
  • Compound interest: Money invested with compound interest grows exponentially, increasing at an ever-accelerating rate.

4. The Mysterious Decoder: Logarithmic Functions (y = log_a(x))

  • Picture a secret code that reveals hidden information. That’s a logarithmic function! Its graph is the inverse of an exponential function, slowly increasing as its input grows rapidly. Imagine:
  • Sound intensity: The loudness of sound, measured in decibels, follows a logarithmic scale, meaning a small increase in decibels represents a significant jump in perceived loudness.
  • Acidity levels: The pH scale uses a logarithmic function to measure acidity, with a small change in pH indicating a tenfold change in acidity.

5. The Shapeshifter: Trigonometric Functions (sin(x), cos(x), tan(x))

  • Imagine waves dancing on the ocean, their peaks and troughs constantly shifting. That’s a trigonometric function! Its graph oscillates up and down, repeating its wavelike pattern at regular intervals. Imagine:
  • Pendulum motion: The swinging of a pendulum can be modeled by a trigonometric function, showing its rhythmic back-and-forth movement.
  • Sound waves: The sound waves we hear are essentially trigonometric functions, with their oscillations translating into the sounds we perceive.

Here are more types you might encounter in Additional Mathematics:

6. Reciprocal Functions:

  • These functions have a shape like a “hyperbola” with two branches that approach, but never touch, the horizontal axis.
  • Example: f(x) = 1/x

7. Absolute Value Functions:

  • They resemble a “V” shape, with a sharp point at the origin.
  • Example: f(x) = |x|

8. Piecewise Functions:

  • These functions are defined by different rules for different parts of their domain, creating a multi-faceted graph.
  • Example: f(x) = {x + 1, if x < 0; x^2, if x ≥ 0}

9. Polynomial Functions:

  • They involve powers of x, including quadratic functions but also extending to higher degrees.
  • Example: f(x) = 3x^3 – 2x^2 + 5x – 1

10. Rational Functions:

  • These functions involve a ratio of two polynomials, creating more complex curves.
  • Example: f(x) = (x^2 + 1)/(x – 2)

11. Periodic Functions:

  • They repeat their patterns at regular intervals, like trigonometric functions but also including other types.
  • Example: f(x) = sin(2x) + cos(x)

12. Recursive Functions:

  • These functions define their output based on previous outputs, creating sequences or patterns that build upon themselves.
  • Example: The Fibonacci sequence, where each term is the sum of the two preceding terms.

13. Parametric Functions:

  • They define both x and y coordinates in terms of a third variable, often used to model motion or curves in space.
  • Example: x(t) = cos(t), y(t) = sin(t) for a circle.

14. Vector-Valued Functions:

  • They produce vectors as outputs, used in physics and engineering to model forces, motion, and fields.
  • Example: f(t) = <t^2, t – 1, 3t^3>

15. Inverse Functions:

  • They “undo” the action of another function, essentially reversing the input-output relationship.
  • Example: The inverse of f(x) = 2x + 3 is f^(-1)(x) = (x – 3)/2

16. Step Functions:

  • These functions have a “staircase” shape, with jumps or discontinuities at certain points.
  • Example: f(x) = {0, if x < 2; 1, if x ≥ 2}

17. Signum Functions:

  • They output 1, 0, or -1 depending on the sign of the input, used for classification and decision-making.
  • Example: sgn(x) = {-1, if x < 0; 0, if x = 0; 1, if x > 0}

18. Floor and Ceiling Functions:

  • They round numbers down or up to the nearest integer, respectively, used for discrete approximations and counting.
  • Example: floor(3.7) = 3, ceiling(3.7) = 4

19. Greatest Integer and Least Integer Functions:

  • They return the largest or smallest integer less than or equal to a given number, used in rounding and truncation.
  • Example: int(4.2) = 4, int(-3.8) = -4

20. Modulus Functions:

  • They give the remainder when a number is divided by another, used in cryptography, modular arithmetic, and cyclic patterns.
  • Example: mod(17, 4) = 1

21. Gamma Function:

  • It extends the concept of factorials to non-integer values, used in probability, statistics, and calculus.
  • Example: Γ(4) = 3! = 6

22. Beta Function:

  • It’s related to the gamma function and has applications in probability distributions and special functions.
  • Example: B(2, 3) = 1/10

23. Hyperbolic Functions:

  • They have similar properties to trigonometric functions but involve the hyperbola instead of the circle, used in calculus and physics.
  • Example: sinh(x) = (e^x – e^(-x))/2

24. Bessel Functions:

  • They arise in wave propagation, heat conduction, and other physical phenomena, involving cylindrical or spherical symmetry.
  • Example: J_0(x) = (sin(x) – cos(x))/x

24. Elliptic Functions:

  • They are more complex functions involving elliptic curves, used in advanced mathematics and physics.
  • Example: K(k) = F(π/2, k), where F is the elliptic integral of the first kind.
y = 2x + 1 Image courtesy Mathway.

Graphing functions

Imagine a function as a hidden landscape, and its graph as a map that unveils its contours and secrets. By mastering graphing techniques, you’ll gain the ability to visualize and navigate this landscape, revealing patterns, trends, and relationships that might be hidden within equations or tables.

Here’s how we’ll embark on this graphical journey in Additional Mathematics:

1. Plotting points:

  • This is the foundation of graphing. We’ll learn how to take input-output pairs from a function’s equation or table and accurately place them on a coordinate plane, creating the initial landmarks on our map.
  • Example: To graph y = 2x + 1, we’d plot points like (0, 1), (1, 3), (-1, -1), and so on.

2. Connecting the dots:

  • Once we have enough points plotted, we’ll discover the shape of the function’s graph by carefully connecting them with a smooth curve. This curve reveals the overall behavior of the function, guiding us through its valleys and peaks.

3. Identifying key features:

  • We’ll learn to pinpoint significant landmarks on the graph, each revealing crucial information about the function’s character:

Intercepts: Where the graph crosses the x-axis (y-intercept) or y-axis (x-intercept), indicating starting points or values where the function becomes zero.

Slope: The steepness of the graph, reflecting how quickly the function’s output changes as the input varies. A positive slope indicates an upward trend, while a negative slope indicates a downward trend.

Symmetry: Whether the graph is mirror-like across certain axes, revealing patterns and potential transformations.

Maximum and minimum points: The highest and lowest points on the graph, representing extreme values or turning points in the function’s behaviour.

4. Interpreting curves:

  • We’ll develop the skill of reading the graph like a language, understanding what its shape, direction, and features tell us about the function’s behaviour. We’ll learn to:

Identify intervals where the function is increasing or decreasing.

Determine where the function is positive or negative.

Estimate values of the function for any input.

Recognise patterns and make predictions based on the graph’s shape.

5. Applying transformations:

  • We’ll explore how to manipulate the graph of a function by shifting it up, down, left, or right, stretching or compressing it, or flipping it over. These transformations allow us to create new functions and understand their relationships to the original one.

6. Using graphs to solve problems:

  • We’ll apply our graphing skills to solve real-world problems, such as:

Finding the time when a projectile reaches its maximum height.

Determining the optimal price for a product to maximise profit.

Predicting the population growth of a city over time.

And many more!

Remember, graphs are not just static images, but powerful tools for exploration, analysis, and problem-solving. By mastering graphing techniques in Additional Mathematics, you’ll unlock a whole new dimension of understanding and apply mathematical concepts to the world around you. Get ready to visualise and conquer the landscapes of functions!

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Mastering the language of transformations

Imagine yourself as a mathematical sculptor, molding clay-like functions into new shapes and forms. This is the essence of mastering transformations, a powerful technique that lets you manipulate graphs and forge entirely new functions from existing ones. Get ready to unleash your inner alchemist and witness the magic of transformations!

Here’s a sneak peek into your superpower kit:

1. The stretching stretch: Picture pinching or pulling a rubber band. That’s like stretching a function vertically or horizontally. You can make it taller and thinner, shorter and wider, or anything in between, all while preserving its basic shape.

  • Vertical stretch: Stretch the y-axis, amplifying the changes in the output for each input. Think of inflating a balloon – small changes in air make a big difference in its size.
  • Horizontal stretch: Stretch the x-axis, compressing or expanding the input range. Imagine stretching a spring – the same distance covers a larger or smaller portion of the spring depending on how much you stretch it.

2. The flipping flip: Picture reversing a reflection in a mirror. That’s like flipping a function over the x-axis or the y-axis. This changes its overall behaviour, creating a mirror image of the original graph.

  • Flip over x-axis: Reflect the graph across the horizontal line (y = 0), turning positive outputs into negative and vice versa. Imagine turning a frown upside down – it becomes a smile!
  • Flip over y-axis: Reflect the graph across the vertical line (x = 0), swapping left and right sides. Think of flipping a pancake in the air – what was once on top is now on the bottom.

3. The shifting slide: Picture moving a picture frame without changing the picture inside. That’s like shifting a function up, down, left, or right. This adds a constant value to the outputs without altering the basic shape of the graph.

  • Vertical shift: Move the graph up or down along the y-axis. Imagine adding or removing bricks from a stack – the shape stays the same, but its position changes.
  • Horizontal shift: Move the graph left or right along the x-axis. Think of sliding a drawer in or out – the contents remain the same, but their location changes.

By combining these transformations, you can create an infinite variety of new functions from old ones. Imagine stretching a graph, flipping it sideways, and then shifting it down – the possibilities are endless! This skill will become your secret weapon, allowing you to:

  • Solve equations graphically: Visualise how transformations move points on the graph, helping you find solutions that satisfy the equation.
  • Analyse function behaviour: Understand how changes in input affect the output by observing the effects of transformations on the graph.
  • Model real-world scenarios: Apply transformations to represent real-world situations, like population growth or projectile motion.
  • Connect different functions: See how seemingly different functions can be related through transformations, revealing hidden patterns and relationships.

Mastering the language of transformations is like gaining fluency in the dialect of functions. It empowers you to understand them deeper, manipulate them with ease, and even create your own mathematical masterpieces. So, hone your skills, embrace the power of transformations, and prepare to reshape the world of functions to your will!

Here’s how functions bridge the gap between abstract mathematics and the real world, empowering you to solve problems and make sense of everyday phenomena:

1. Modelling population growth:

  • Imagine tracking how a city’s population expands over time. Exponential functions can model this growth, predicting future population sizes and informing decisions about infrastructure, resource allocation, and public services.
  • Example: P(t) = P_0 * e^(kt), where P(t) is the population at time t, P_0 is the initial population, k is the growth rate, and e is the base of the natural logarithm.

2. Calculating rocket trajectories:

  • Launching a rocket into space involves precise calculations of its path and velocity. Functions come to the rescue, modeling factors like gravity, thrust, and air resistance to determine the optimal trajectory for a successful mission.
  • Example: h(t) = -16t^2 + v_0t + h_0, where h(t) is the height at time t, v_0 is the initial velocity, and h_0 is the initial height.

3. Analysing investment trends:

  • Financial experts rely on functions to track stock prices, predict market fluctuations, and make informed investment decisions. Compound interest, for example, is a powerful exponential function that can help you grow your savings over time.
  • Example: A = P(1 + r/n)^(nt), where A is the final amount, P is the principal, r is the annual interest rate, n is the number of times interest is compounded per year, and t is the number of years.

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4. Optimising production:

  • Factories and businesses use functions to optimise production processes, minimise costs, and maximise profits. Functions can model relationships between input resources, output products, and costs, helping to make informed decisions about production levels and resource allocation.
  • Example: C(x) = ax^2 + bx + c, where C(x) is the cost of producing x units of a product, and a, b, and c are constants representing fixed costs, variable costs, and setup costs.

5. Predicting weather patterns:

  • Meteorologists use complex mathematical models, based on functions, to forecast weather patterns, track storms, and issue warnings. These models analyse factors like temperature, pressure, humidity, and wind speed to predict future weather conditions.
  • Example: Atmospheric models often involve partial differential equations, which are functions that relate multiple variables and their rates of change.

6. Designing structures:

  • Engineers rely on functions to design bridges, buildings, and other structures that can withstand forces and stresses. Functions model the distribution of weight, tension, and compression, ensuring structural integrity and safety.
  • Example: F = kx, where F is the force applied to a spring, k is the spring constant, and x is the displacement of the spring.

7. Modelling disease spread:

  • Epidemiologists use functions to track the spread of infectious diseases and predict outbreak patterns. Functions model factors like transmission rates, contact patterns, and population immunity, informing public health measures to control outbreaks.
  • Example: The SIR model (Susceptible-Infected-Recovered) uses differential equations to model the dynamics of disease transmission.

These are just a few examples of the countless ways functions connect mathematics to the real world. By understanding functions, you gain the power to analyse, predict, and shape the world around you. You’ll unlock a deeper understanding of the patterns and relationships that govern our lives, and you’ll be equipped to make informed decisions that impact our society, environment, and future.

See also:

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