Math Problem Statement

Write a sine function in the form y = a sin(bx - c) + d for the three graphs below.

Solution

Let's analyze the sine function graphs given in the problem and determine the functions in the form y=asin(bxc)+dy = a \sin(bx - c) + d for each:

1. Analysis of the First Graph:

  • Amplitude (aa): The height from the centerline (0) to the peak is about 2, so a=2a = 2.
  • Period (2πb\frac{2\pi}{b}): The period is the distance between two peaks, which appears to be π\pi, so b=2b = 2.
  • Phase shift (cc): It looks like there is no horizontal shift, so c=0c = 0.
  • Vertical shift (dd): The graph is centered around y=0y = 0, so d=0d = 0.

The function is: y=2sin(2x)y = 2 \sin(2x)

2. Analysis of the Second Graph:

  • Amplitude (aa): The amplitude is 3.
  • Period (2πb\frac{2\pi}{b}): The distance between two peaks is about 6, which gives b=π3b = \frac{\pi}{3}.
  • Phase shift (cc): The graph starts at 0, indicating c=0c = 0.
  • Vertical shift (dd): The graph is centered around y=0y = 0.

The function is: y=3sin(π3x)y = 3 \sin\left(\frac{\pi}{3}x\right)

3. Analysis of the Third Graph:

  • This graph is described to have a maximum at (π2,7)\left(\frac{\pi}{2}, 7\right) and a minimum at (3π2,1)\left(\frac{3\pi}{2}, -1\right).
  • Amplitude (aa): The difference between the maximum and minimum is 7(1)=87 - (-1) = 8, so a=4a = 4.
  • Period (2πb\frac{2\pi}{b}): The distance between π2\frac{\pi}{2} and 3π2\frac{3\pi}{2} is π\pi, so b=2b = 2.
  • Phase shift (cc): The maximum occurs at π2\frac{\pi}{2}, suggesting a phase shift of π2\frac{\pi}{2}.
  • Vertical shift (dd): The midline is at 7+(1)2=3\frac{7 + (-1)}{2} = 3.

The function is: y=4sin(2xπ2)+3y = 4 \sin(2x - \frac{\pi}{2}) + 3

Would you like more details or have any questions on these solutions?

Relative Questions:

  1. How do you determine the period of a sine function from a graph?
  2. What effect does changing the amplitude have on the graph of a sine function?
  3. How do phase shifts impact the position of sine and cosine graphs?
  4. Can you derive the formula for the period of a sine function from its general form?
  5. What are the differences between horizontal and vertical shifts in trigonometric functions?

Tip:

For a sine function y=asin(bxc)+dy = a \sin(bx - c) + d, remember that aa affects the amplitude, bb affects the period (2πb\frac{2\pi}{b}), cc affects the horizontal shift, and dd adjusts the vertical shift.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Sine Functions
Graph Analysis

Formulas

y = a sin(bx - c) + d
Period of sine function = 2π/b
Amplitude = |a|

Theorems

Sine function transformation

Suitable Grade Level

Grades 10-12