Math Problem Statement

y = cos 2x

Solution

The function y=cos(2x)y = \cos(2x) represents a cosine function with an angular frequency that is twice the normal frequency of the basic cosine function y=cos(x)y = \cos(x).

Here are some important characteristics of this function:

  1. Amplitude: The amplitude of cos(2x)\cos(2x) is 1, since there is no vertical scaling factor in front of the cosine function.

  2. Period: The period of cos(x)\cos(x) is 2π2\pi, but for cos(2x)\cos(2x), the period is shortened. The period of cos(kx)\cos(kx) is given by 2πk\frac{2\pi}{|k|}. Therefore, the period of cos(2x)\cos(2x) is: Period=2π2=π\text{Period} = \frac{2\pi}{2} = \pi This means that the function completes one full cycle over an interval of π\pi.

  3. Frequency: The frequency is the reciprocal of the period. Since the period is π\pi, the frequency is 1π\frac{1}{\pi}.

  4. Phase Shift: There is no phase shift, as there is no horizontal translation.

  5. Vertical Shift: There is no vertical shift, since no constant is added or subtracted to the function.

Would you like more details on graphing or properties of this function?

Here are some related questions to deepen understanding:

  1. How does changing the coefficient of xx in cos(kx)\cos(kx) affect the graph?
  2. What is the difference in the period between cos(x)\cos(x) and cos(3x)\cos(3x)?
  3. How would the function y=2cos(2x)y = 2 \cos(2x) differ from y=cos(2x)y = \cos(2x)?
  4. Can you explain how the derivative of y=cos(2x)y = \cos(2x) would look?
  5. What happens to the graph of y=cos(2x)y = \cos(2x) if we add a phase shift of π4\frac{\pi}{4}?

Tip: The angular frequency 2x2x compresses the graph horizontally by a factor of 2, meaning the function oscillates more quickly.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Cosine Function
Angular Frequency
Periodic Functions

Formulas

y = cos(kx)
Period of cos(kx) = 2π / |k|
Frequency = 1 / Period

Theorems

Periodic Function Theorem

Suitable Grade Level

Grades 10-12