Math Problem Statement

Find the value of the trigonometric function. Find tan(θ), given that sin(θ) = -3/4 and θ is in quadrant II.

Solution

We are tasked with finding tanθ\tan \theta given that:

sinθ=34andθ is in Quadrant II.\sin \theta = -\frac{3}{4} \quad \text{and} \quad \theta \text{ is in Quadrant II}.

Step-by-Step Solution:

  1. Use 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 Solving for cos2θ\cos^2 \theta: cos2θ=1916=716\cos^2 \theta = 1 - \frac{9}{16} = \frac{7}{16} Thus: cosθ=±74\cos \theta = \pm \frac{\sqrt{7}}{4}

  2. Determine the sign of cosθ\cos \theta: Since θ\theta is in Quadrant II, cosine is negative in this quadrant. Therefore: cosθ=74\cos \theta = -\frac{\sqrt{7}}{4}

  3. Find tanθ\tan \theta: The tangent function is defined as: tanθ=sinθcosθ\tan \theta = \frac{\sin \theta}{\cos \theta} Substituting the values: tanθ=3474=37\tan \theta = \frac{-\frac{3}{4}}{-\frac{\sqrt{7}}{4}} = \frac{3}{\sqrt{7}} To rationalize the denominator: tanθ=37×77=377\tan \theta = \frac{3}{\sqrt{7}} \times \frac{\sqrt{7}}{\sqrt{7}} = \frac{3 \sqrt{7}}{7}

Thus, the value of tanθ\tan \theta is:

tanθ=377\tan \theta = \frac{3 \sqrt{7}}{7}

Would you like further details or have any questions?

Here are 5 related questions:

  1. How can we find cotθ\cot \theta given the value of tanθ\tan \theta?
  2. What is the value of secθ\sec \theta for the given problem?
  3. How do we determine the quadrant of an angle based on the signs of sine and cosine?
  4. Can you explain why cosine is negative in Quadrant II?
  5. How can we use the Pythagorean identity to find cosθ\cos \theta for any trigonometric function?

Tip: Always remember that the signs of trigonometric functions depend on the quadrant in which the angle lies.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Trigonometric Functions
Quadrants

Formulas

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

Theorems

Pythagorean Identity

Suitable Grade Level

Grades 9-12