Math Problem Statement

The function g is related to a parent function f(x) = sin(x). g(x) = sin(2x βˆ’ πœ‹) (a) Describe the sequence of transformations from f to g. The function g(x) is obtained by a ---Select--- of 2 and a ---Select--- of πœ‹ 2 to the right. (b) Sketch the graph of g.

The x y-coordinate plane is given. A curve has a cycle that repeats horizontally every 4πœ‹. One cycle starts on the x-axis at x = 0, goes down and right becoming less steep, changes direction at the point (πœ‹, βˆ’1), goes up and right becoming more steep, crosses the x-axis at x = 2πœ‹, goes up and right becoming less steep, changes direction at the point (3πœ‹, 1), goes down and right becoming more steep, and stops on the x-axis at x = 4πœ‹. The next cycle starts at x = 4πœ‹.

The x y-coordinate plane is given. A curve has a cycle that repeats horizontally every 4πœ‹. One cycle starts on the x-axis at x = 0, goes down and right becoming less steep, changes direction at the point (πœ‹, βˆ’2), goes up and right becoming more steep, crosses the x-axis at x = 2πœ‹, goes up and right becoming less steep, changes direction at the point (3πœ‹, 2), goes down and right becoming more steep, and stops on the x-axis at x = 4πœ‹. The next cycle starts at x = 4πœ‹.

The x y-coordinate plane is given. A curve has a cycle that repeats horizontally every πœ‹. One cycle starts on the x-axis at x = 0, goes down and right becoming less steep, changes direction at the point (πœ‹β„4, βˆ’1), goes up and right becoming more steep, crosses the x-axis at x = πœ‹β„2, goes up and right becoming less steep, changes direction at the point (3πœ‹β„4, 1), goes down and right becoming more steep, and stops on the x-axis at x = πœ‹. The next cycle starts at x = πœ‹.

The x y-coordinate plane is given. A curve has a cycle that repeats horizontally every πœ‹. One cycle starts on the x-axis at x = 0, goes down and right becoming less steep, changes direction at the point (πœ‹β„4, βˆ’2), goes up and right becoming more steep, crosses the x-axis at x = πœ‹β„2, goes up and right becoming less steep, changes direction at the point (3πœ‹β„4, 2), goes down and right becoming more steep, and stops on the x-axis at x = πœ‹. The next cycle starts at x = πœ‹.

(c) Use function notation to write g in terms of f. g(x) = f 

Solution

Let's work through each part step by step:

(a) Describe the sequence of transformations from f(x)=sin⁑(x)f(x) = \sin(x) to g(x)=sin⁑(2xβˆ’Ο€)g(x) = \sin(2x - \pi)

We can break down the transformation process into two parts:

  1. Horizontal compression by a factor of 2: The coefficient of 22 in front of xx inside the sine function indicates a horizontal compression by a factor of 12\frac{1}{2}. This affects the period of the sine function, making it half of the original period.

  2. Horizontal shift to the right by Ο€2\frac{\pi}{2}: The βˆ’Ο€- \pi inside the argument of the sine function results in a horizontal shift. Specifically, since g(x)=sin⁑(2xβˆ’Ο€)g(x) = \sin(2x - \pi), this corresponds to a shift to the right by Ο€2\frac{\pi}{2}.

Thus, the transformation is:

  • A horizontal compression by a factor of 2 and a shift to the right by Ο€2\frac{\pi}{2}.

(b) Sketch the graph of g(x)g(x)

Based on the transformations in part (a):

  • The horizontal compression by 2 means the period of the sine wave is now 2Ο€2=Ο€\frac{2\pi}{2} = \pi instead of 2Ο€2\pi.
  • The horizontal shift to the right by Ο€2\frac{\pi}{2} means the entire sine curve starts Ο€2\frac{\pi}{2} units later along the x-axis.

The key points on the graph:

  • One cycle of the sine curve begins at x=Ο€2x = \frac{\pi}{2}, goes down, reaches a minimum at x=Ο€2+Ο€4=3Ο€4x = \frac{\pi}{2} + \frac{\pi}{4} = \frac{3\pi}{4}, goes up through the x-axis at x=Ο€2+Ο€2=Ο€x = \frac{\pi}{2} + \frac{\pi}{2} = \pi, and continues similarly.

The new period is Ο€\pi, and the amplitude remains 1 (since there is no vertical scaling).

(c) Use function notation to write g(x)g(x) in terms of f(x)f(x)

The parent function is f(x)=sin⁑(x)f(x) = \sin(x), and we need to express g(x)g(x) in terms of ff.

Since g(x)=sin⁑(2xβˆ’Ο€)g(x) = \sin(2x - \pi), and f(x)=sin⁑(x)f(x) = \sin(x), we can express g(x)g(x) as: g(x)=f(2xβˆ’Ο€)g(x) = f(2x - \pi)

This shows that g(x)g(x) is simply the sine function f(x)f(x), with the argument xx replaced by 2xβˆ’Ο€2x - \pi.


Do you want further details or have any questions?

Here are five related questions to deepen your understanding:

  1. How does a horizontal compression affect the period of any trigonometric function?
  2. What is the difference between a horizontal shift and a vertical shift in trigonometric graphs?
  3. How would the graph change if we added a vertical shift to g(x)g(x)?
  4. What would be the period of g(x)=sin⁑(3xβˆ’Ο€)g(x) = \sin(3x - \pi)?
  5. How would you express g(x)=cos⁑(2xβˆ’Ο€)g(x) = \cos(2x - \pi) in terms of f(x)=cos⁑(x)f(x) = \cos(x)?

Tip:

For horizontal transformations, remember that a multiplier inside the function (like 2x2x) affects the period, while a constant shift (like βˆ’Ο€-\pi) affects the phase.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Trigonometry
Transformations of functions

Formulas

g(x) = sin(2x - Ο€)
f(x) = sin(x)
g(x) = f(2x - Ο€)

Theorems

Trigonometric transformations
Sine function period and phase shift

Suitable Grade Level

Grades 10-12