ACT Math : Transformation

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #451 : Advanced Geometry

If this is a sine graph, what is the phase displacement?Screen_shot_2013-07-16_at_10.04.45_am

Possible Answers:

0

π

2π

4π

(1/2)π

Correct answer:

0

Explanation:

The phase displacement is the shift from the center of the graph. Since this is a sine graph and the sin(0) = 0, this is in phase.

Example Question #1 : Transformations

If this is a cosine graph, what is the phase displacement?Screen_shot_2013-07-16_at_10.04.45_am

Possible Answers:

4π

π

2π

(1/2)π

0

Correct answer:

π

Explanation:

The phase displacement is the shift of the graph. Since cos(0) = 1, the phase shift is π because the graph is at its high point then.

Example Question #1 : Transformation

A regular pentagon is graphed in the standard (x,y) coordinate plane. Which of the following are the coordinates for the vertex P?

Screen_shot_2013-06-03_at_1.02.45_pm

Possible Answers:

Correct answer:

Explanation:

Regular pentagons have lines of symmetry through each vertex and the center of the opposite side, meaning the y-axis forms a line of symmetry in this instance. Therefore, point P is negative b units in the x-direction, and c units in the y-direction. It is a reflection of point (b,c) across the y-axis.

Example Question #1 : Transformation

If g(x) is a transformation of f(x) that moves the graph of f(x) four units up and three units left, what is g(x) in relation to f(x)?

Possible Answers:

Correct answer:

Explanation:

To solve this question, you must have an understanding of standard transformations. To move a function along the x-axis in the positive direction, you must subtract the value from the operative x-value. For example, to move a function, f(x), five units to the left would be f(x+5).

To shift a function along the y-axis in the positive direction, you must add the value to the overall function. For example, to move a function, f(x), three units up would be f(x)+3.

The question asks us to move the function, f(x), left three units and up four units. f(x+3) will move the function three units to the left and f(x)+4 will move it four units up.

Together, this gives our final answer of f(x+3)+4.

Example Question #2 : Transformation

What is the period of the function?

Screen_shot_2013-07-16_at_10.04.45_am

Possible Answers:

4π

2π

1

π

3π

Correct answer:

4π

Explanation:

The period is the time it takes for the graph to complete one cycle.

In this particular case we have a sine curve that starts at 0 and completes one cycle when it reaches .

Therefore, the period is 

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