Math Problem Statement

The angle [\theta_1] is located in Quadrant [\text{II}], and

[\sin(\theta_1)=\dfrac{9}{41}] .

Solution

Given that θ1\theta_1 is located in Quadrant II and sin(θ1)=941\sin(\theta_1) = \dfrac{9}{41}, we can find additional trigonometric values for θ1\theta_1. Here's the process:

Step 1: Understand the Sine Function

  • sin(θ1)=oppositehypotenuse=941\sin(\theta_1) = \dfrac{\text{opposite}}{\text{hypotenuse}} = \dfrac{9}{41}
  • In Quadrant II, sine is positive, and cosine is negative.

Step 2: Use the Pythagorean Identity to Find cos(θ1)\cos(\theta_1)

The Pythagorean identity is:

sin2(θ1)+cos2(θ1)=1\sin^2(\theta_1) + \cos^2(\theta_1) = 1

Substitute sin(θ1)=941\sin(\theta_1) = \dfrac{9}{41}:

(941)2+cos2(θ1)=1\left( \dfrac{9}{41} \right)^2 + \cos^2(\theta_1) = 1

811681+cos2(θ1)=1\dfrac{81}{1681} + \cos^2(\theta_1) = 1

cos2(θ1)=1811681=16001681\cos^2(\theta_1) = 1 - \dfrac{81}{1681} = \dfrac{1600}{1681}

Step 3: Solve for cos(θ1)\cos(\theta_1)

cos(θ1)=±160041=±4041\cos(\theta_1) = \pm \dfrac{\sqrt{1600}}{41} = \pm \dfrac{40}{41}

Since θ1\theta_1 is in Quadrant II, cos(θ1)\cos(\theta_1) is negative:

cos(θ1)=4041\cos(\theta_1) = -\dfrac{40}{41}

Step 4: Find tan(θ1)\tan(\theta_1)

The tangent is defined as:

tan(θ1)=sin(θ1)cos(θ1)\tan(\theta_1) = \dfrac{\sin(\theta_1)}{\cos(\theta_1)}

Substitute the values:

tan(θ1)=9/4140/41=940\tan(\theta_1) = \dfrac{9/41}{-40/41} = -\dfrac{9}{40}

Summary of Trigonometric Values:

  • sin(θ1)=941\sin(\theta_1) = \dfrac{9}{41}
  • cos(θ1)=4041\cos(\theta_1) = -\dfrac{40}{41}
  • tan(θ1)=940\tan(\theta_1) = -\dfrac{9}{40}

Would you like more details or have any questions?

Here are 5 related questions to expand on this:

  1. How do the trigonometric identities change across different quadrants?
  2. What is the relationship between sine, cosine, and tangent in general?
  3. Can you derive the secant, cosecant, and cotangent values from this information?
  4. How would the values change if θ1\theta_1 were in Quadrant III?
  5. Why is the cosine value negative in Quadrant II?

Tip: In trigonometry, always be mindful of the signs of the functions based on the quadrant of the angle.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Quadrants
Pythagorean Identity
Sine and Cosine

Formulas

Pythagorean identity: \(\sin^2(\theta) + \cos^2(\theta) = 1\)
Tangent definition: \(\tan(\theta) = \dfrac{\sin(\theta)}{\cos(\theta)}\)

Theorems

Pythagorean Theorem

Suitable Grade Level

Grades 10-12