Math Problem Statement

sin2θ2\theta=1 solve for 0θ2π\ll\theta\ll2\pi

Solution

To solve the equation sin2θ=1\sin 2\theta = 1 for 0<θ<2π0 < \theta < 2\pi, follow these steps:

Step 1: Find the general solution for 2θ2\theta

The sine function equals 1 at specific points: sin2θ=1    2θ=π2+2kπ,kZ\sin 2\theta = 1 \implies 2\theta = \frac{\pi}{2} + 2k\pi, \quad k \in \mathbb{Z} where kk is any integer.

Step 2: Solve for θ\theta

Divide both sides by 2 to solve for θ\theta: θ=π2+2kπ2=π4+kπ\theta = \frac{\frac{\pi}{2} + 2k\pi}{2} = \frac{\pi}{4} + k\pi

Step 3: Determine valid solutions within the given range

Now, we consider values of θ\theta in the range 0<θ<2π0 < \theta < 2\pi. We test values of kk:

  1. For k=0k = 0: θ=π4\theta = \frac{\pi}{4}
  2. For k=1k = 1: θ=π4+π=5π4\theta = \frac{\pi}{4} + \pi = \frac{5\pi}{4}
  3. For k=2k = 2: θ=π4+2π=9π4\theta = \frac{\pi}{4} + 2\pi = \frac{9\pi}{4} However, 9π4\frac{9\pi}{4} is greater than 2π2\pi, so it is not within the range.

Step 4: List the solutions

The solutions for θ\theta in the range 0<θ<2π0 < \theta < 2\pi are: θ=π4,5π4\theta = \frac{\pi}{4}, \frac{5\pi}{4}

These are the values of θ\theta that satisfy the equation.

Would you like more details or have any questions?


Here are 5 related questions:

  1. What are the general solutions for sinx=1\sin x = -1?
  2. How does the range of the sine function affect the solutions of trigonometric equations?
  3. Can you solve cos2θ=1\cos 2\theta = 1 for the same interval?
  4. How would the solution change if the equation was sin2θ=1\sin 2\theta = -1?
  5. What are the implications of solving sin2θ=12\sin 2\theta = \frac{1}{2} within the same interval?

Tip: Always check your solutions by substituting them back into the original equation to verify correctness.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Trigonometric Equations
Sine Function

Formulas

sin(x) = 1 implies x = π/2 + 2kπ, k ∈ Z

Theorems

General solutions of trigonometric equations

Suitable Grade Level

Grades 10-12