Math Problem Statement

Suppose that θ is an angle in standard position whose terminal side intersects the unit circle at (-√7/4, -3/4). Find the exact values of sec(θ), cot(θ), and sin(θ).

Solution

Let's break down the problem from the image.

Problem Recap:

You are given a point on the unit circle at (74,34)\left(-\frac{\sqrt{7}}{4}, -\frac{3}{4}\right) and need to find the exact values of secθ\sec\theta, cotθ\cot\theta, and sinθ\sin\theta, where θ\theta is the angle whose terminal side passes through this point.

Step 1: Determine sinθ\sin\theta and cosθ\cos\theta

Since the point lies on the unit circle, we know: x=cosθ=74,y=sinθ=34x = \cos\theta = -\frac{\sqrt{7}}{4}, \quad y = \sin\theta = -\frac{3}{4}

Step 2: Calculate secθ\sec\theta

secθ=1cosθ=174=47=477\sec\theta = \frac{1}{\cos\theta} = \frac{1}{-\frac{\sqrt{7}}{4}} = -\frac{4}{\sqrt{7}} = -\frac{4\sqrt{7}}{7}

Step 3: Calculate cotθ\cot\theta

cotθ=cosθsinθ=7434=73\cot\theta = \frac{\cos\theta}{\sin\theta} = \frac{-\frac{\sqrt{7}}{4}}{-\frac{3}{4}} = \frac{\sqrt{7}}{3}

Step 4: Confirm sinθ\sin\theta

Given directly from the yy-coordinate of the point: sinθ=34\sin\theta = -\frac{3}{4}

Summary of Exact Values:

secθ=477,cotθ=73,sinθ=34\sec\theta = -\frac{4\sqrt{7}}{7}, \quad \cot\theta = \frac{\sqrt{7}}{3}, \quad \sin\theta = -\frac{3}{4}

Would you like to go into further detail on any of these steps or have any specific questions?

Related Questions:

  1. How do you find cosθ\cos\theta and sinθ\sin\theta if only given θ\theta?
  2. Why does the point lie on the unit circle?
  3. How is secθ\sec\theta related to cosθ\cos\theta?
  4. What is the relationship between cotθ\cot\theta and tanθ\tan\theta?
  5. How can you derive tanθ\tan\theta given cotθ\cot\theta?

Tip:

Always ensure to rationalize the denominator when expressing values such as secθ\sec\theta or cotθ\cot\theta to make them cleaner and more standardized.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Unit Circle
Trigonometric Functions

Formulas

sin(θ) = y-coordinate
cos(θ) = x-coordinate
sec(θ) = 1/cos(θ)
cot(θ) = cos(θ)/sin(θ)

Theorems

Pythagorean Identity

Suitable Grade Level

Grades 10-12