Math Problem Statement

Find an equation for a sinusoidal function that has a period 2(pi), amplitude 1,and contains the point (pi/2,-3)

Solution

Let's find the equation of the sinusoidal function with the given properties.

Step 1: General Form of the Sinusoidal Function

The general form of a sinusoidal function is:

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

Where:

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

Step 2: Identify the Given Parameters

  1. Amplitude (AA): Given as 1, so A=1A = 1.
  2. Period: Given as 2π2\pi. The period is given by 2πB\frac{2\pi}{|B|}. Since the period is 2π2\pi, we have: 2πB=2π\frac{2\pi}{|B|} = 2\pi Simplifying gives B=1|B| = 1. So, B=1B = 1.
  3. Point: The function passes through the point (π2,3)\left(\frac{\pi}{2}, -3\right).

Step 3: Set Up the Equation

Now we substitute the known values into the equation:

y=sin(x+C)+Dy = \sin(x + C) + D

Step 4: Use the Point (π2,3)\left(\frac{\pi}{2}, -3\right) to Find CC and DD

Substitute x=π2x = \frac{\pi}{2} and y=3y = -3 into the equation:

3=sin(π2+C)+D-3 = \sin\left(\frac{\pi}{2} + C\right) + D

This simplifies to:

-3 = 1 + D \quad \text{(since \sin\left(\frac{\pi}{2} + C\right)reachesitsmaximumvalueof1whenreaches its maximum value of 1 whenC = 0)}

D=4D = -4

Now the equation is:

y=sin(x+C)4y = \sin(x + C) - 4

Step 5: Determine CC Using the Known Point

Given that sin(π2+C)=1\sin\left(\frac{\pi}{2} + C\right) = 1, and the sine function equals 1 at π2\frac{\pi}{2}, CC should be 0.

Therefore, the equation becomes:

y=sin(x)4y = \sin(x) - 4

Final Answer:

The equation of the sinusoidal function that meets all the given conditions is:

y=sin(x)4\boxed{y = \sin(x) - 4}

Would you like more details or have any questions?

Relative Questions:

  1. How does the vertical shift DD affect the graph of a sinusoidal function?
  2. What would the equation look like if the function had a different phase shift CC?
  3. How can you determine the maximum and minimum values of a sinusoidal function?
  4. What happens to the function y=sin(x)y = \sin(x) if the amplitude is changed to 2?
  5. How does the sine function compare to the cosine function in terms of phase shifts?

Tip:

Remember that the vertical shift DD moves the entire graph up or down, depending on its sign. It represents the midline of the sinusoidal wave.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Sinusoidal Functions

Formulas

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

Theorems

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Suitable Grade Level

Grades 10-12