Math Problem Statement

Find the terminal point on the unit circle determined by 7π/4 radians. Use exact values, not decimal approximations.

Solution

To solve this problem, we need to find the terminal point on the unit circle for the angle 7π4\frac{7\pi}{4} radians. Here's how we approach it:

  1. Understand the angle position:

    • The angle 7π4\frac{7\pi}{4} radians is in the fourth quadrant because it is greater than 3π2\frac{3\pi}{2} radians but less than 2π2\pi radians.
  2. Find the reference angle:

    • The reference angle is the acute angle formed with the x-axis. For 7π4\frac{7\pi}{4}, the reference angle is: 2π7π4=π4.2\pi - \frac{7\pi}{4} = \frac{\pi}{4}.
  3. Determine the coordinates:

    • The unit circle coordinates for an angle with reference angle π4\frac{\pi}{4} are: (cos(π4),sin(π4))=(22,22).(\cos(\frac{\pi}{4}), \sin(\frac{\pi}{4})) = \left( \frac{\sqrt{2}}{2}, \frac{\sqrt{2}}{2} \right).
    • In the fourth quadrant, the cosine (x-coordinate) is positive, and the sine (y-coordinate) is negative. Thus, the coordinates are: (22,22).\left( \frac{\sqrt{2}}{2}, -\frac{\sqrt{2}}{2} \right).

Final Answer:

The terminal point on the unit circle is: (22,22).\boxed{\left( \frac{\sqrt{2}}{2}, -\frac{\sqrt{2}}{2} \right)}.

Let me know if you need further details or explanations!


Related Questions:

  1. What is the terminal point for 5π4\frac{5\pi}{4} radians on the unit circle?
  2. How do you find the terminal point for negative angles?
  3. What are the coordinates of the terminal point for π3\frac{\pi}{3} radians?
  4. Why is the reference angle important for finding terminal points?
  5. How do you use symmetry of the unit circle to determine terminal points quickly?

Tip:

Always determine the quadrant of the angle first. This will help you correctly assign signs to the coordinates.

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Math Problem Analysis

Mathematical Concepts

Unit Circle
Trigonometry
Radians
Reference Angles

Formulas

Reference angle: θ_reference = 2π - θ (for angles in the fourth quadrant)
Coordinates of a point on the unit circle: (cos(θ), sin(θ))

Theorems

Unit Circle Trigonometric Functions

Suitable Grade Level

Grades 10-12