GCSE Mathematics (9-1)

13.3 Transformations of graphs — Practise with help

Try each question before opening a hint. Move through the steps in order.

Warm-up: remember

  1. Find f(2)f(2) if f(x)=x2f(x)=x^2.
  2. State the yy-intercept of y=x+3y=x+3.
  3. Give the image of (1,4)(1,4) after moving it two units up.
  4. Expand (x+2)2(x+2)^2.
Answers

44; (0,3)(0,3); (1,6)(1,6); x2+4x+4x^2+4x+4.

Practise with help

1. Translate y=x2y=x^2 two units right.

Hint

For a right shift, replace xx with x−2x-2.

Next step

Substitute x−2x-2 wherever the original rule has xx.

Full working

The new rule is y=(x−2)2y=(x-2)^2.

2. Starting with y=x2y=x^2, move the graph two units right and three units down.

Hint

Make the horizontal change inside the brackets and the vertical change outside.

Next step

First write (x−2)2(x-2)^2, then subtract three.

Full working

y=(x−2)2−3y=(x-2)^2-3. The turning point is (2,−3)(2,-3).

3. Reflect y=f(x)y=f(x) in the xx-axis.

Hint

Change the sign of every output.

Next step

Write the new output as −f(x)-f(x).

Full working

The reflected rule is y=−f(x)y=-f(x).

4. A point (2,5)(2,5) lies on y=f(x)y=f(x). Find its image under reflection in the xx-axis.

Hint

Keep the input fixed and change the sign of the output.

Next step

The new output is −5-5.

Full working

The image is (2,−5)(2,-5), because the input stays fixed and the output changes sign.

Settings

Colour scheme

Applies to every book you read here.

Reading theme

Applies to every book you read here.