Math Problem Statement

answer

Let θ be an angle such that sec θ = 17/15 and cot θ > 0. Find the exact values of tan θ and sin θ.

Solution

To find the exact values of tanθ\tan \theta and sinθ\sin \theta given secθ=1715\sec \theta = \frac{17}{15} and cotθ>0\cot \theta > 0, we can follow these steps:

Step 1: Determine the Quadrant

Given that secθ=1715\sec \theta = \frac{17}{15} (which is positive) and cotθ>0\cot \theta > 0, we know that both cosine and cotangent are positive. This means that θ\theta is in the first quadrant because in the first quadrant, all trigonometric functions are positive.

Step 2: Find cosθ\cos \theta

Since secθ=1cosθ\sec \theta = \frac{1}{\cos \theta}, we can find cosθ\cos \theta:

cosθ=1secθ=1517\cos \theta = \frac{1}{\sec \theta} = \frac{15}{17}

Step 3: Find sinθ\sin \theta

Using the Pythagorean identity:

sin2θ+cos2θ=1\sin^2 \theta + \cos^2 \theta = 1

Substitute cosθ=1517\cos \theta = \frac{15}{17}:

sin2θ+(1517)2=1\sin^2 \theta + \left(\frac{15}{17}\right)^2 = 1

sin2θ+225289=1\sin^2 \theta + \frac{225}{289} = 1

sin2θ=1225289=289225289=64289\sin^2 \theta = 1 - \frac{225}{289} = \frac{289 - 225}{289} = \frac{64}{289}

sinθ=64289=817\sin \theta = \sqrt{\frac{64}{289}} = \frac{8}{17}

Since θ\theta is in the first quadrant, sinθ\sin \theta is positive:

sinθ=817\sin \theta = \frac{8}{17}

Step 4: Find tanθ\tan \theta

Using the identity tanθ=sinθcosθ\tan \theta = \frac{\sin \theta}{\cos \theta}:

tanθ=8171517=815\tan \theta = \frac{\frac{8}{17}}{\frac{15}{17}} = \frac{8}{15}

Conclusion

The exact values are:

tanθ=815,sinθ=817\tan \theta = \frac{8}{15}, \quad \sin \theta = \frac{8}{17}

Would you like more details on any step or have any questions?

Here are some related questions for further exploration:

  1. How do you find the values of other trigonometric functions like cotθ\cot \theta, cscθ\csc \theta, and cosθ\cos \theta?
  2. What is the significance of the Pythagorean identity in trigonometry?
  3. How can you determine the quadrant of an angle if given different trigonometric conditions?
  4. How do the signs of trigonometric functions change across different quadrants?
  5. What is the geometric interpretation of these trigonometric values on the unit circle?

Tip: Understanding how to use the Pythagorean identities can greatly simplify solving trigonometric problems involving angles and their respective functions.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Trigonometric Identities
Pythagorean Theorem

Formulas

sec θ = 1 / cos θ
sin^2 θ + cos^2 θ = 1
tan θ = sin θ / cos θ

Theorems

Pythagorean Identity

Suitable Grade Level

Grades 10-12