Math Problem Statement

Jan is doing research on the phenomena of vibrations. She compiles a series of results and obtains the following graph on the computer screen. What rule represents this function?

Solution

The graph provided in the image appears to be a sinusoidal wave. From the general shape of the function and the grid, it seems that this is a trigonometric function, likely of the form:

f(x)=Asin(Bx+C)+Dorf(x)=Acos(Bx+C)+Df(x) = A \sin(Bx + C) + D \quad \text{or} \quad f(x) = A \cos(Bx + C) + D

Let's analyze the key features of the graph to determine the equation:

1. Amplitude (A):

  • The maximum value of the function is 3, and the minimum value is -3, so the amplitude is A=3A = 3.

2. Period:

  • The graph appears to complete one full cycle between 0 and 2π2\pi. The period TT is 2π2\pi. For a sine or cosine function, the period is given by 2πB\frac{2\pi}{B}. In this case, B=1B = 1.

3. Horizontal Shift (C):

  • The function has not been shifted horizontally, so C=0C = 0.

4. Vertical Shift (D):

  • There is no vertical shift in the graph because the function oscillates symmetrically about the x-axis, meaning D=0D = 0.

Function Type (Cosine):

  • The graph appears to resemble a cosine function starting at a maximum point (3 at x=0x = 0) rather than starting from 0, which is typical of a cosine function. So, the function is more likely to be:

f(x)=3cos(x)f(x) = 3 \cos(x)

Conclusion:

The rule representing this function is:

f(x)=3cos(x)f(x) = 3 \cos(x)

Would you like further details on this solution or have any questions?

Related Questions:

  1. How does changing the amplitude AA affect the graph of a trigonometric function?
  2. What is the effect of a horizontal shift CC on the graph of sine or cosine functions?
  3. How can we derive the period of any trigonometric function given its equation?
  4. What happens if a vertical shift DD is introduced to the function?
  5. Can you describe the graph of f(x)=sin(x)f(x) = \sin(x) and how it compares to f(x)=cos(x)f(x) = \cos(x)?

Tip:

When identifying the rule of a trigonometric graph, always check for key characteristics like amplitude, period, phase shift, and vertical shift. This helps in constructing the exact equation.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Graph Analysis
Cosine Function

Formulas

f(x) = A cos(Bx + C) + D

Theorems

Period of Trigonometric Functions
Amplitude in Trigonometry

Suitable Grade Level

Grades 10-12