Unit 3

Transformations


Practice Solutions

Practice 3.1B Solutions

Use these solutions to correct your work. When finished, give yourself a grade using the Practice Assessment rubric.
 
Pages 28 to 30, questions 1a to 1d, 2a to 2d, 3a to 3c, 6a, 6b, 7a to 7d, and 10a to 10c.

a.
x
  fx=2x+1   gx=−fx   hx=f−x
  -4   -7   7   9
  -2   -3   3   5
  0   1   -1   1
  2   5   -5   -3
  4   9   -9   -7

b.

c.
The points on gx have the same x-values as fx, but the y-values have opposite signs. There is an invariant point on the x-axis at −0.5,0.
The points on hx have the same y-values as fx, but the x-values have opposite signs. There is an invariant point on the y-axis at 0,1.
d.
The graph of gx is a reflection of fx in the x-axis. The graph of hx is a reflection of fx in the y-axis.
a.
x   fx=x2   gx=3fx   hx=13fx
  -6   36   108   12
  -3   9   27   3
  0   0   0   0
  3   9   27   3
  6   36   108   12
b.
c.
The points on gx have the same x-values as fx, but the y-values have been multiplied by 3.
The point 0,0 is invariant.
The points on hx have the same x-values, but the y-values have been multiplied by 13.
The point 0,0 is invariant.
d.
The graph of gx is a vertical stretch about the x-axis of fx by a factor of 3. The graph of hx is a vertical stretch about the x-axis of fx by a factor of 13.

a.

The equation of the reflected function is gx=−3x.

The domain is x∣x∈R and the range is y∣y∈R for both functions.
b.

The equation of the reflected function is

hx=−x2+1=−x2−1

The domain of gx is x∣x∈R and the range is y∣y≥1,y∈R.

The domain of hx is x∣x∈R and the range is y∣y≤−1,y∈R.
c.

The equation of the reflected function is

kx=−1x

The domain of hx is x∣x≠0,x∈R and the range is y∣y≠0,y∈R.

The domain of kx is x∣x≠0,x∈R and the range is x∣x≠0,y∈R.
a.
The domain of the transformed function is x∣−6≤x≤6x∈R. The range is y∣−8≤y≤8,y∈R.


b.
The vertical stretch increased the range by a factor of 2. The domain was not changed.
a.
The graph of function fx has been stretched vertically about the x-axis by a factor of 4.
gx=4fx
b.
The graph of function fx has been reflected in the x-axis.
gx=−fx
c.
The graph of function fx has been stretched horizontally about the y-axis by a factor of 13.
gx=f3x
d.
The graph of function fx has been reflected in the y-axis.
gx=f−x
a.


b.

c.
The order does not matter because both produced the same graph. Neither person is correct.