1. Transformations: Review Transformations
1.6 Transformations of
Functions
Transformations
Transformations: Review
Transformations
We will be looking at functions from our library of functions and seeing how various modifications to the functions transform them.
Transformations
Transformations
Transformations
Transformations
Transformations

2. VERTICAL TRANSLATIONS
Above is the graph of
As you can see, a number added or subtracted from a function will cause a vertical shift or translation of the function.
VERTICAL TRANSLATIONS
What would f(x) + 1 look like? (This would mean taking all the function values and adding 1 to them).
What would f(x) - 3 look like? (This would mean taking all the function values and subtracting 3 from them).

3. VERTICAL TRANSLATIONS
The graph f(x) + k, where k is any real number is the graph of f(x) that is vertically shifted by k. If k is positive it will shift up. If k is negative it will shift down
VERTICAL TRANSLATIONS
Above is the graph of
What would f(x) + 2 look like?
What would f(x) - 4 look like?

4. HORIZONTAL TRANSLATIONS
Above is the graph of
As you can see, a number added or subtracted from the x will cause a horizontal shift or translation in the function but opposite way of the sign of the number.
What would f(x-1) look like? (This would mean taking all the x values and subtracting 1 from them before putting them in the function).
What would f(x+2) look like? (This would mean taking all the x values and adding 2 to them before putting them in the function).

5. HORIZONTAL TRANSLATIONS
The graph f(x-h), where h is any real number is the graph of f(x) that is horizontally shifted by h.
So the graph f(x-h), where h is any real number is the graph of f(x) but horizontally shifted by h.
shift right 3
Above is the graph of
What would f(x+1) look like?
So shift along the x-axis by 3
What would f(x-3) look like?

6. We could have a function that is transformed or translated both vertically AND horizontally.
up 3
left 2
Above is the graph of
What would the graph of look like?

7. Compressing S t r e t c h i n g VERTICAL DILATION HORIZONTAL DILATION
and
Compressing
VERTICAL
DILATION
HORIZONTAL
DILATION

8. VERTICAL
DILATION
If we multiply a function by a non-zero real number it has the affect of either stretching or compressing the function because it causes the function value (the y value) to be multiplied by that number.

9. Notice for any x on the graph, the new (red) graph has a y value that is 2 times as much as the original (blue) graph's y value.
Notice for any x on the graph, the new (green) graph has a y value that is 4 times as much as the original (blue) graph's y value.
The graph af(x), where a is any real number GREATER THAN 1, is the graph of f(x) that is vertically stretched or dilated by a factor of a.
Above is the graph of
What would 2f(x) look like?
What would 4f(x) look like?

10. What if the value of a was positive but less than 1?
The graph af(x), where a is 0 < a < 1, is the graph of f(x) that is vertically compressed or dilated by a factor of a.
Notice for any x on the graph, the new (green) graph has a y value that is 1/4 as much as the original (blue) graph's y value.
Notice for any x on the graph, the new (red) graph has a y value that is 1/2 as much as the original (blue) graph's y value.
Above is the graph of
What would 1/2 f(x) look like?
What would 1/4 f(x) look like?

11. Compressing S t r e t c h i n g HORIZONTAL DILATION and
If we have x-variable multiplied by a non-zero real number c, that is f(cx), it has the affect of either horizontal stretching or compressing the function, because for graphing each x value is to be divided by that number.
The graph f(cx), where c is c > 1, is the graph of f(x) that is horizontally compressed by a factor of c (x-values becoming smaller).
The graph f(cx), where c is 0 < c < 1, is the graph of f(x) that is horizontally stretched by a factor of c (x-values becoming bigger).

12. (The new graph is obtained by reflecting the function over the x-axis)
What if the value of a was negative?
The graph - f(x) is a reflection about the x-axis of the graph of f(x).
(The new graph is obtained by reflecting the function over the x-axis)
Notice any x on the new (red) graph has a y value that is the negative of the original (blue) graph's y value.
Above is the graph of
What would - f(x) look like?

13. There is one last transformation we want to look at.
The graph f(-x) is a reflection about the y-axis of the graph of f(x). (The new graph is obtained by reflecting the function over the y-axis)
Notice any x on the new (red) graph has an x value that is the negative of the original (blue) graph's x value.
Above is the graph of
What would f(-x) look like? (This means we are going to take the negative of x before putting in the function)

14. Summary of Transformations So Far
FOLLOW ORDER OF OPERATIONS
If a > 1, then vertical dilation or stretch by a factor of a
If 0 < a < 1, then vertical dilation or compression (shrink) by a factor of a
If a < 0, then reflection about the x-axis (as well as being dilated by a factor of a)
vertical translation of k
f(-x) reflection about y-axis
horizontal translation of h (opposite sign of number with the x)

15. Graphing from a parent function by transformations continues:
Example
Describe how the graph of can be obtained by transforming the graph of Sketch its graph.
Solution
Since the basic graph is the vertex of the parabola is shifted right 4 units. Since the coefficient of is –3, the graph is stretched vertically by a factor of 3 and then reflected across the x-axis. The constant +5 indicates the vertex shifts up 5 units.
shift 4 units right
shift 5 units up
vertical stretch by a factor of 3
reflect across the x-axis

16. There is one more Transformation we need to know.
Always follow ORDER of OPERATIONS
If a > 1, then vertical dilation or stretch by a factor of a
If 0 < a < 1, then vertical dilation or compression by a factor of a
If a < 0, then reflection about the x-axis (as well as being dilated by a factor of a)
vertical translation of k
f(-x) reflection about y-axis
horizontal translation (opposite sign of number with the x)
horizontal dilation by a factor of 1/c

17. Practice time!
Given function f(x) graph