Math Problem Statement

Given sin(θ) = -3/4 and tan(θ) > 0, find the values of cos(θ), tan(θ), cot(θ), sec(θ), and csc(θ).

Solution

The question given is asking to solve for trigonometric values, given the information:

  • sinθ=34\sin \theta = -\frac{3}{4}
  • tanθ>0\tan \theta > 0

This implies that θ\theta lies in the third quadrant, where both sine and cosine are negative, and tangent is positive.

Let’s compute all the required values:

1. Using the Pythagorean Identity:

sin2θ+cos2θ=1\sin^2\theta + \cos^2\theta = 1 Substitute sinθ=34\sin\theta = -\frac{3}{4}: (34)2+cos2θ=1\left(-\frac{3}{4}\right)^2 + \cos^2\theta = 1 916+cos2θ=1\frac{9}{16} + \cos^2\theta = 1 cos2θ=1916=1616916=716\cos^2\theta = 1 - \frac{9}{16} = \frac{16}{16} - \frac{9}{16} = \frac{7}{16} cosθ=716=74(negative in the third quadrant).\cos\theta = -\sqrt{\frac{7}{16}} = -\frac{\sqrt{7}}{4} \quad \text{(negative in the third quadrant)}.

2. Compute tanθ\tan\theta:

tanθ=sinθcosθ=3474=37=377.\tan\theta = \frac{\sin\theta}{\cos\theta} = \frac{-\frac{3}{4}}{-\frac{\sqrt{7}}{4}} = \frac{3}{\sqrt{7}} = \frac{3\sqrt{7}}{7}.

3. Compute cotθ\cot\theta:

cotθ=1tanθ=73.\cot\theta = \frac{1}{\tan\theta} = \frac{\sqrt{7}}{3}.

4. Compute 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}.

5. Compute cscθ\csc\theta:

cscθ=1sinθ=134=43.\csc\theta = \frac{1}{\sin\theta} = \frac{1}{-\frac{3}{4}} = -\frac{4}{3}.

Summary of Results:

  • sinθ=34\sin\theta = -\frac{3}{4}
  • cosθ=74\cos\theta = -\frac{\sqrt{7}}{4}
  • tanθ=377\tan\theta = \frac{3\sqrt{7}}{7}
  • cotθ=73\cot\theta = \frac{\sqrt{7}}{3}
  • secθ=477\sec\theta = -\frac{4\sqrt{7}}{7}
  • cscθ=43\csc\theta = -\frac{4}{3}

Would you like further clarification or detailed steps for any part of the solution?

Related Questions:

  1. What are the quadrant-specific signs of trigonometric functions?
  2. How do you use the Pythagorean identity for solving trigonometric values?
  3. Why is tanθ\tan\theta positive while sinθ\sin\theta and cosθ\cos\theta are negative?
  4. How can rationalizing fractions like 37\frac{3}{\sqrt{7}} be simplified for answers?
  5. What is the importance of the unit circle in solving trigonometric equations?

Tip: Always double-check the quadrant to assign the correct signs to sinθ\sin\theta, cosθ\cos\theta, and other values!

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Quadrants in Trigonometry
Pythagorean Identity

Formulas

sin^2(θ) + cos^2(θ) = 1
tan(θ) = sin(θ) / cos(θ)
cot(θ) = 1 / tan(θ)
sec(θ) = 1 / cos(θ)
csc(θ) = 1 / sin(θ)

Theorems

Pythagorean Identity

Suitable Grade Level

Grades 10-12