Big Ideas Math Algebra 2, 2014
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Big Ideas Math Algebra 2, 2014 View details
4. Transformations of Exponential and Logarithmic Functions
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Exercise 20 Page 322

Start by performing a horizontal translation.

Transformation: Translation 5 units to the right followed by a horizontal stretch by a factor of 2.
Graph:

Practice makes perfect
We want to graph the given exponential function as a transformation of its parent function. g(x)=4^(0.5x- 5)

Notice that the function is of the form g(x)=4^(ax- h), where a= 0.5, or 1 2, and h= 5. Therefore, the graph of g is a translation 5 units to the right, followed by a horizontal stretch by a factor of 2 of the graph of its parent function. Let's show the transformations one at a time.

Translation

We will first consider the function y=4^(x-5). This is a horizontal translation of f(x)=4^x to the right by 5 units.

Horizontal Stretch

Be aware that 0.5= 12. Therefore, if in y=4^(x-5) we multiply the x-variable by 0.5, we obtain a horizontal stretch by a factor of 2. The resulting function is g(x)=4^(0.5x-5).

Extra

Possible Transformations

The following table illustrates the general form for all possible transformations of functions.

Transformations of f(x)
Vertical Translations Translation up k units, k>0 y=f(x)+ k
Translation down k units, k>0 y=f(x)- k
Horizontal Translations Translation right h units, h>0 y=f(x- h)
Translation left h units, h>0 y=f(x+ h)
Vertical Stretch or Compression Vertical stretch, a>1 y= af(x)
Vertical compression, 0< a< 1 y= af(x)
Horizontal Stretch or Compression Horizontal stretch, b>1 y=f(1/bx)
Horizontal compression, 0< b<1 y=f(1/bx)
Reflections In the x-axis y=- f(x)
In the y-axis y=f(- x)