Math Problem Statement

Terminal point if t=-41pi/4

Solution

To find the terminal point on the unit circle corresponding to t=41π4t = -\frac{41\pi}{4}, we can follow these steps:

Step 1: Reduce the angle

The angle t=41π4t = -\frac{41\pi}{4} is greater than 2π2\pi in magnitude, so we first reduce it to an equivalent angle between 00 and 2π2\pi. To do this, we add multiples of 2π2\pi to get a positive equivalent angle.

2π=8π42\pi = \frac{8\pi}{4}

So, add 2π2\pi multiple times until the angle falls within the range [0,2π][0, 2\pi]. We do this by calculating:

t+10π=41π4+40π4=π4t + 10\pi = -\frac{41\pi}{4} + \frac{40\pi}{4} = -\frac{\pi}{4}

Thus, t=π4t = -\frac{\pi}{4} is the equivalent angle within [0,2π][0, 2\pi].

Step 2: Find the terminal point

The angle π4-\frac{\pi}{4} corresponds to the same terminal point as 7π4\frac{7\pi}{4} in the standard position (since it's a counterclockwise rotation from 2π2\pi).

On the unit circle, the terminal point corresponding to 7π4\frac{7\pi}{4} is:

(cos(7π4),sin(7π4))\left( \cos\left(\frac{7\pi}{4}\right), \sin\left(\frac{7\pi}{4}\right) \right)

We know that:

cos(7π4)=22andsin(7π4)=22\cos\left(\frac{7\pi}{4}\right) = \frac{\sqrt{2}}{2} \quad \text{and} \quad \sin\left(\frac{7\pi}{4}\right) = -\frac{\sqrt{2}}{2}

Final Answer:

The terminal point is (22,22)\left( \frac{\sqrt{2}}{2}, -\frac{\sqrt{2}}{2} \right).


Would you like more details on this process or further clarification?

Here are some related questions for deeper understanding:

  1. How do you reduce negative angles to positive ones in trigonometry?
  2. What are the coordinates of common angles on the unit circle?
  3. How does the unit circle help in understanding trigonometric functions?
  4. What is the significance of the terminal point on the unit circle?
  5. Can the same process be used for positive angles larger than 2π2\pi?

Tip: When working with angles on the unit circle, reducing them modulo 2π2\pi simplifies your calculations.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Unit Circle
Angle Reduction

Formulas

Equivalent angle formula: t + 2nπ where n is an integer
Coordinates on the unit circle: (cos(θ), sin(θ))

Theorems

Unit Circle Theorem
Trigonometric Function Properties

Suitable Grade Level

Grades 10-12