Math Problem Statement

Find an equation for a sinusoidal function that has a period 2(pi), amplitude 2,and contains the point (pi,2)

Solution

To find the equation of a sinusoidal function that meets the given conditions, let's start by using the general form of a sinusoidal function:

y=Asin(Bx+C)+Dy = A \sin(Bx + C) + D

Where:

  • AA is the amplitude.
  • BB affects the period of the function.
  • CC is the phase shift.
  • DD is the vertical shift.

Step 1: Identify the given parameters

  1. Amplitude (AA): Given as 2, so A=2A = 2.
  2. Period: Given as 2π2\pi. The period of a sinusoidal function is 2πB\frac{2\pi}{|B|}. Since the period is 2π2\pi, we have: 2πB=2π\frac{2\pi}{|B|} = 2\pi Simplifying this gives B=1|B| = 1. So B=1B = 1 (assuming a positive value for simplicity).
  3. Point: The function passes through the point (π,2)(\pi, 2).

Step 2: Substitute the known values into the equation

Now, we substitute the known values into the equation: y=2sin(x+C)+Dy = 2 \sin(x + C) + D

Step 3: Use the point (π,2)(\pi, 2) to find CC and DD

We know the function passes through (π,2)(\pi, 2). Substituting x=πx = \pi and y=2y = 2 into the equation:

2=2sin(π+C)+D2 = 2 \sin(\pi + C) + D

This simplifies to:

1=sin(π+C)+D21 = \sin(\pi + C) + \frac{D}{2}

Step 4: Analyze sin(π+C)\sin(\pi + C)

  • sin(π+C)=sin(C)\sin(\pi + C) = -\sin(C), so:

1=sin(C)+D21 = -\sin(C) + \frac{D}{2}

At this point, we have a system of equations. If we assume no vertical shift D=0D = 0 for simplicity, then:

1=sin(C)1 = -\sin(C)

So sin(C)=1\sin(C) = -1, meaning C=π2C = -\frac{\pi}{2}.

Step 5: Final equation

Substitute C=π2C = -\frac{\pi}{2} and D=0D = 0 back into the equation:

y=2sin(xπ2)y = 2 \sin\left(x - \frac{\pi}{2}\right)

So, the equation of the sinusoidal function is:

y=2sin(xπ2)\boxed{y = 2 \sin\left(x - \frac{\pi}{2}\right)}

This satisfies the given conditions: a period of 2π2\pi, an amplitude of 2, and it contains the point (π,2)(\pi, 2).

Would you like more details or have any questions?

Relative Questions:

  1. How does changing the amplitude affect the graph of a sinusoidal function?
  2. What effect does the phase shift CC have on the graph of y=Asin(Bx+C)+Dy = A \sin(Bx + C) + D?
  3. How do you determine the vertical shift DD for a sinusoidal function?
  4. What is the relationship between the period and the coefficient BB in a sinusoidal function?
  5. How can we find the equation of a sinusoidal function given multiple points?

Tip:

When dealing with sinusoidal functions, always remember that the period is determined by BB, and this influences how "stretched" or "compressed" the wave appears on the graph.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Sinusoidal Functions

Formulas

General form of a sinusoidal function: y = A sin(Bx + C) + D

Theorems

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Suitable Grade Level

Grades 11-12