Math Problem Statement

Find all values of x such that sin(2x) = sin(x) and
0 ≀ x ≀ 2πœ‹. (Enter your answers as a comma-separated list.)

Solution

To solve the equation sin⁑(2x)=sin⁑(x)\sin(2x) = \sin(x) within the interval 0≀x≀2Ο€0 \leq x \leq 2\pi, we can use trigonometric identities and properties of sine functions.

Step 1: Use the identity for sin⁑(2x)\sin(2x)

We know that: sin⁑(2x)=2sin⁑(x)cos⁑(x)\sin(2x) = 2\sin(x)\cos(x) So, the equation becomes: 2sin⁑(x)cos⁑(x)=sin⁑(x)2\sin(x)\cos(x) = \sin(x)

Step 2: Factor the equation

We can factor out sin⁑(x)\sin(x) from both sides: sin⁑(x)β‹…(2cos⁑(x)βˆ’1)=0\sin(x) \cdot (2\cos(x) - 1) = 0

This equation will be satisfied if either: sin⁑(x)=0\sin(x) = 0 or 2cos⁑(x)βˆ’1=02\cos(x) - 1 = 0

Step 3: Solve each equation separately

Case 1: sin⁑(x)=0\sin(x) = 0

The sine function equals zero at: x=0,Ο€,2Ο€x = 0, \pi, 2\pi

Case 2: 2cos⁑(x)βˆ’1=02\cos(x) - 1 = 0

Solve for cos⁑(x)\cos(x): cos⁑(x)=12\cos(x) = \frac{1}{2} The cosine function equals 12\frac{1}{2} at: x=Ο€3,5Ο€3x = \frac{\pi}{3}, \frac{5\pi}{3}

Step 4: Combine all solutions

The values of xx that satisfy the original equation are: x=0,Ο€3,Ο€,5Ο€3,2Ο€x = 0, \frac{\pi}{3}, \pi, \frac{5\pi}{3}, 2\pi

Thus, the solution set is: 0,Ο€3,Ο€,5Ο€3,2Ο€\boxed{0, \frac{\pi}{3}, \pi, \frac{5\pi}{3}, 2\pi}

Would you like further details on how these solutions were found or have any other questions?

Here are five related questions you might find interesting:

  1. How do we solve trigonometric equations involving tangent?
  2. What are the general solutions for the equation sin⁑(x)=k\sin(x) = k?
  3. How does the double-angle identity for sine function work in other equations?
  4. How can we solve cos⁑(2x)=cos⁑(x)\cos(2x) = \cos(x) for 0≀x≀2Ο€0 \leq x \leq 2\pi?
  5. What are the zeros of the sine function on a given interval?

Tip: When solving trigonometric equations, always check if you can factor the equation to make it simpler to solve.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Trigonometric Identities
Sine Function

Formulas

Double-angle identity for sine: \( \sin(2x) = 2\sin(x)\cos(x) \)

Theorems

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Suitable Grade Level

Grades 10-12