Pearson Algebra 2 Common Core, 2011
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Pearson Algebra 2 Common Core, 2011 View details
8. Graphing Radical Functions
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Exercise 39 Page 419

What differences do you see between the given function and the parent function? Apply those transformations to the graph of the parent function, f(x)=sqrt(x).

Graph:

Domain: x≥1
Range: y ≥ 3

Practice makes perfect

The given function is a square root function. f(x)= 1/2sqrt(x- 1)+ 3 The graph of it will be a transformed version of the parent function, y=sqrt(x). Square root functions typically follow the same general format. f(x)= asqrt(x- h)+ k

Graphing the Function

To graph the given function, let's show the possible transformations of f(x)=sqrt(x).

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 Shrink Vertical stretch, a>1 y= af(x)
Vertical shrink, 0< a<1 y= af(x)
Reflections In the x-axis y= - f(x)
In the y-axis y= f(- x)

Using the table, we can graph the function as a series of transformations. Let's begin with the parent function.

Next, we will multiply the y-coordinates by a= 12. This shrinks the parent graph by a factor of 12.

Now, we will translate the graph 3 units up by adding 3 to each of the y-coordinates.

For the last transformation, we will translate the graph 1 unit to the right. To do this, we will add 1 to each x-coordinate.

Finally, we have the graph of the given function.

Finding the Domain and Range

To determine the domain of the function, recall that the radicand cannot be negative. x-1 ≥ 0 ⇔ x ≥ 1 Therefore, the possible values of x are those such that x≥ 1. By substituting the minimum value of the domain into the function, we can find the minimum value of the range.

f(x)=1/2sqrt(x-1)+3
f( 1)=1/2sqrt(1-1)+3
f(1)=1/2*0+3
f(1)=3

This tells us that the range is all values of y such that y≥ 3. Domain:& x ≥ 1 Range:& y≥ 3