Rules Of Transformations

Rules of transformations help in transforming the function f(x) to a new function f'(x), because of the change in its domain or the range values. The function can be transformed vertically, horizontally, or it can be stretched or compressed, with the help of these rules of transformation. The rules of transformations can also be represented graphically.

Let us learn the rules of transformation, its graphical representations, with the help of examples, FAQs.

Function transformation rules help in transforming the function based on the change of either the domain or the range of the function. For a function y = f(x), the domain is the x value and the range is the f(x) or the y value of the function. The transformation of a function to change the domain of the function is to replace the x value with a new value of x such as x + a, 5x, x - 3, x/2. Similarly the change of the range of the function is possible by replacing f(x) with -f(x), f(x) + 3, f(x) - 2, f(x)/4.

Rules of transformation represent these changes in the x or y values of the function. The six important rules of transformation are as follows.

1. Vertical Transformation : The function f(x) is shifted up by 'a' units upwards for the function f(x) + a. And the function f(x) is shifted vertically doward
2. Horizontal Transformation: The function f(x) is shifted towards the left for the new function f(x + a). And it is transformed towards the right on replacing f(x) with f(x - a).
3. Flipped Transformation about the X-axis: The function f(x) is flipped about the x-axis by writing it as f(-x).
4. Mirror Transformation About the Y-axis: The function f(x) is changed to -f(x) to obtain a mirror transformation about the y-axis.
5. Stretched/Compressed Vertical Transformation: The function f(x) is stretched/compressed vertically if a constant 'c' transforms it to cf(x). If c >1 then it is stretched vertically, and if 0 < c < 1 then it is compressed vertically.
6. Stretched/Compressed Horizontal Transformation: The function f(x) is stretched/compressed horizontally if a constant 'c' transforms it to f(cx). If c > 1 then it is compressed horizontally, and if 0 < c < 1 then it is stretched horizontally.

The rules of transformation for functions can be represented graphically across the coordinate axis. The domain of the function - the x value can be represented along the x-axis, and the range of the function - the y value can be represented along the y-axis. The change in the domain or the range of the function, can be understood by the change in the x-values and the y-values. The function transformation rules can be shown as change in the graph of the function in the coordinate axis.

Vertical Transformation:

In the vertical transformation, the graph moves either up or down.

• If the function f(x) has been vertical shifted upwards by 'a' units then the result is the function f(x) + a. In this case, the point (x, y) with reference to the function f(x) changes to (x, y + a) for the new function f(x) + a.
• If the function f(x) has been vertically shifted downwards by 'a' units then the result is the function f(x) - a. In this case, the point (x, y) with reference to f(x, y), has been changed to (x, y - a), for the new transformed function f(x) - a.

As an example the function f(x) = x³+ 2x² has been vertically transformed by 4 units for f(x) = x³ + 2x² + 4., and a point (x, y) with reference to the earlier function is not represented as (x, y + 4).

Horizontal Transformation

In this transformation, the graph of a function moves to the left side or right side. The graph of a function f(x)

• moves to the right if x is replaced by x - a. In this case, a point (x, y) of f(x) becomes (x + a, y) of f(x - a).
• moves to the left if x is replaced by x + a. In this case, a point (x, y) of f(x) becomes (x - a, y) of f(x + a).

Let us consider a function f(x) = 2x + 3, to be shifted horizontally about the x-axis, by 2 units to the left and the new function would be f(x + 2) = 2(x + 2) + 3. And a point (x, y) with reference to the earlier function is now represented as (x - 2, y).

Flipped Transformation about the x-axis

The function f(x) is flipped transformed about the x-axis by writing it as -f(x) and it is a mirror reflection of the function f(x) about the x-axis. The point (x, y) with reference to the function f(x) is now transformed to (x, -y).

An an example the function f(x) = 3x +2 is transformed to is flipped across the x-axis and is represented as -f(x) = -(3x + 2). The point (x, y) has not been changed to (x, -y).

Mirror Transformation about the y-axs

The function f(x) is mirror transformed or reflected about the y-axis by representing it as f(-x). The point (x, y) with reference to the function f(x) is now changed to (-x, y) with reference to the new function f(-x). The function is observed to be reflected about the y-axis.

As an example let us take a function f(x) = 5x + 1, which is reflected about the y-axis to obtain f(-x) = 5(-x) + 1 = -5x + 1. The point (x, y) is now changed to (-x, y).

Stretch/Compression of Vertical Transformation

The function f(x) is stretched/compressed vertically by using a constant 'c' and it is now written as cf(x) to represent a new stretched/compressed function. The function cf(x) is

• stretched vertically if c > 1
• compressed vertically if 0 < c < 1.

The point (x, y) with reference to the original function is now changed to (x, cy). Here is an example of vertical stretch.

The blue curve in the graph shows the stretched function, and the orange curve shows the original function. Note that a point (1, 1) on the orange curve has now becomes (1, 3) on the blue curve.

Stretch/Compression of Horizontal Transformation

The function f(x) is stretched/compressed horizontally by using a constant 'c' and it is now written as f(cx) to represent a new stretched/compressed function. The function f(cx) is

• stretched horizontally if 0 < c < 1.
• compressed horizontally if c > 1.

The point (x, y) with reference to the original function is now changed to (x/c, y). Here is an example of vertical stretch.

The blue curve in the graph shows the stretched function, and the orange curve shows the original function. Note that a point (1, 1) on the orange curve has now becomes (3, 1) on the blue curve.

☛Related Topics

• Transformations
• X and Y Coordinates
• Axis of Symmetry
• Coordinate Geometry
• Polar Coordinates

What Are The Rules Of Transformations In Functions?

The rules of transformations are useful for transforming a given function f(x) into a new function g(x). These transformations are a result of the change in the domain and range of the original function. The rules of transformation can be represented graphically to show change the shift in the curve of the function f(x).

What Are the Four Important Rules Of Transformations?

The four important rules of transformation are vertical transformation, horizontal transformation, stretched transformation, compressed transformation. The details of each of the transformations functions rules are as follows.

• Vertical Transformation: The function f(x) is transformed vertically to f(x) + a, or f(x) - a.
• Horizontal Transformation: The function f(x) is transformed horizontally to f(x + a), or f(x - a).
• Stretched/Compressed Horizontal Transformation: The function f(x) is transformed horizontally as f(cx),where it is stretched if 0 < c < 1 and compressed if c > 1.
• Stretched/Compressed Vertical Transformation: The function f(x) is transformed vertically as cf(x),where it is stretched if c > 1 and compressed if 0 < c < 1.

What Are The Formulas For The Rules Of Transformations?

There are different formulas for different rules of transformation. For vertically transformation the function f(x) is transformed to f(x) + a or f(x) - a. For horizontal transformation the function f(x) is transformed to f(x + a) or f(x - a). Further for stretched or compressed transformation is it f(cx) or cf(x). 

How Do We Apply The Rules Of Transformations?

The rules of transformations are applicable by changing the coordinates. For example, the horizontal transformation f(x + a) of f(x) moves f(x) 'a' units (where a > 0) to the left side.

What Are The Applications Of Rules Of Transformations?

The rules of transformation are applicable if the domain or the range of the functions are changed. These rules can be used to shit or change the graph of the given function in the coordinate axis.