Grade 11 → Functions and Graphs → Transformations of Functions ↓
Translations
In the study of functions and graphs, it is important to understand transformations to understand the behavior of graphs. An important type of transformation is a translation. Translations are essentially shifts of the graph in the coordinate plane. They do not change the shape or orientation of the graph; rather, they simply move it to a different location.
What is translation?
Translation in mathematics means to move a figure, line, or graph without rotating it, resizing it, or altering it. When we translate a graph, we slide it horizontally, vertically, or both. In function notation, translation involves adding or subtracting constants to the function or its variables.
Types of translation
There are two main types of translation:
- Horizontal translation: Moving the graph to the left or right.
- Vertical translation: Moving the graph up or down.
Horizontal translation
Horizontal translation involves shifting the graph to the right or left by a certain number of units. The function f(x)
is translated horizontally by changing the variable to f(x - k)
, where k
is the number of units by which the graph is shifted.
- If
k > 0
, the graph movesk
units to the right. - If
k < 0
, the graph moves|k|
units to the left.
Example of horizontal translation
Consider the function f(x) = x^2
, which is a basic quadratic function that forms a parabola with its vertex at the origin (0,0).
f(x) = (x - 3)^2
This is the translation of the function f(x) = x^2
by 3 units to the right.
Vertical translation
Vertical translation involves moving the graph up or down by a certain number of units. The function f(x)
is translated vertically by adding a constant c
to the entire function: f(x) + c
.
- If
c > 0
, the graph moves upc
units. - If
c < 0
, the graph moves down|c|
units.
Example of vertical translation
Consider the function f(x) = x^2
.
f(x) = x^2 + 4
This function results in a transformation f(x) = x^2
4 units upward.
Combining translations
Translations can be combined to move the graph both horizontally and vertically. For example, you could have a function that undergoes both types of translations:
f(x) = (x - h)^2 + k
In this case, h
represents the horizontal shift, and k
represents the vertical shift. The function f(x) = (x - h)^2 + k
transforms the original function f(x) = x^2
to the right by h
units and up by k
units.
- If
h > 0
, moveh
units to the right; ifh < 0
, move|h|
units to the left. - If
k > 0
, move upk
units; ifk < 0
, move down|k|
units.
Example of a combined translation
Let's apply both horizontal and vertical translation to the function f(x) = x^2
:
f(x) = (x - 2)^2 + 3
Here, the function is translated 2 units to the right and 3 units up.
Understanding the effects of translation
Translation in mathematics means understanding how each operation affects the state of the graph. Once you understand how translation works, it becomes easier to predict graphical changes and apply this knowledge to complex problems.
Practical examples and exercises
To make these concepts clear, let's consider some more examples and exercises:
Example 1
Consider this function:
g(x) = (x + 1)^2 - 2
Determine the translation applied to f(x) = x^2
:
- The graph is shifted horizontally 1 unit to the left, because
x + 1
represents motion in the opposite direction. - The graph is shifted vertically downward by 2 units because
- 2
term decreases the output for each correspondingx
value.
Example 2
Let's solve this translation:
h(x) = 2x - 5
Pay attention here:
- No horizontal translation exists because there is no addition or subtraction to the function argument affecting
x
. - The vertical translation is 5 units downward, which translates every point on the graph parallelly.
Key points
- Translations only affect the position of the graph, not its size or shape.
- Horizontal and vertical translation can be done simultaneously.
- Translation is needed to build a knowledge graph and understand the tasks visually.
Interactive views
The next time you see a function modification, imagine how these constants move your graph on the plane. Understanding translations not only helps in graph drawing but also enhances your ability to predict function behaviors without calculations.
Conclusion
Once the use of positive and negative values for h
(horizontal) and k
(vertical) is understood, translating graphs becomes straightforward. This understanding provides insight into function modifications and how they appear graphically, which lays the groundwork for more advanced studies into transformations such as reflections and rotations in mathematical analysis.