Math Problem Statement

Find the values of the trigonometric functions of 𝜃 from the information given. tan(𝜃) = −3, sin(𝜃) > 0

Solution

Given the information:

  1. tan(θ)=3\tan(\theta) = -3
  2. sin(θ)>0\sin(\theta) > 0

Step 1: Determine the quadrant

  • Since tan(θ)=3\tan(\theta) = -3, the tangent is negative.
  • Since sin(θ)>0\sin(\theta) > 0, the sine is positive.

Tangent is negative and sine is positive in Quadrant II.

Step 2: Use tan(θ)=sin(θ)cos(θ)\tan(\theta) = \frac{\sin(\theta)}{\cos(\theta)}

  • tan(θ)=3\tan(\theta) = -3 implies sin(θ)cos(θ)=3\frac{\sin(\theta)}{\cos(\theta)} = -3.

In Quadrant II, sine is positive and cosine is negative. Let’s assume: sin(θ)=3kandcos(θ)=k\sin(\theta) = 3k \quad \text{and} \quad \cos(\theta) = -k Substitute into the tangent formula: 3kk=3\frac{3k}{-k} = -3 This satisfies the equation, so the sine and cosine values are proportional to 3 and -1.

Step 3: Calculate sin(θ)\sin(\theta) and cos(θ)\cos(\theta)

To find the exact values, we use the identity: sin2(θ)+cos2(θ)=1\sin^2(\theta) + \cos^2(\theta) = 1 Substitute sin(θ)=3k\sin(\theta) = 3k and cos(θ)=k\cos(\theta) = -k into the equation: (3k)2+(k)2=1(3k)^2 + (-k)^2 = 1 9k2+k2=19k^2 + k^2 = 1 10k2=110k^2 = 1 k2=110,k=110k^2 = \frac{1}{10}, \quad k = \frac{1}{\sqrt{10}}

Step 4: Final values of sin(θ)\sin(\theta) and cos(θ)\cos(\theta)

  • sin(θ)=3k=310=31010\sin(\theta) = 3k = \frac{3}{\sqrt{10}} = \frac{3\sqrt{10}}{10}
  • cos(θ)=k=110=1010\cos(\theta) = -k = -\frac{1}{\sqrt{10}} = -\frac{\sqrt{10}}{10}

Step 5: Calculate the remaining trigonometric functions

  • tan(θ)=3\tan(\theta) = -3 (given)
  • cot(θ)=1tan(θ)=13=13\cot(\theta) = \frac{1}{\tan(\theta)} = \frac{1}{-3} = -\frac{1}{3}
  • sec(θ)=1cos(θ)=10\sec(\theta) = \frac{1}{\cos(\theta)} = -\sqrt{10}
  • csc(θ)=1sin(θ)=103\csc(\theta) = \frac{1}{\sin(\theta)} = \frac{\sqrt{10}}{3}

Final answers:

  • sin(θ)=31010\sin(\theta) = \frac{3\sqrt{10}}{10}
  • cos(θ)=1010\cos(\theta) = -\frac{\sqrt{10}}{10}
  • tan(θ)=3\tan(\theta) = -3
  • cot(θ)=13\cot(\theta) = -\frac{1}{3}
  • sec(θ)=10\sec(\theta) = -\sqrt{10}
  • csc(θ)=103\csc(\theta) = \frac{\sqrt{10}}{3}

Would you like more details or further clarifications?

Related questions:

  1. How do you determine the quadrant based on sine and tangent signs?
  2. Can you explain the identity sin2(θ)+cos2(θ)=1\sin^2(\theta) + \cos^2(\theta) = 1 further?
  3. How is sec(θ)\sec(\theta) calculated from cos(θ)\cos(\theta)?
  4. How do inverse trigonometric functions relate to this problem?
  5. What are the possible ranges for trigonometric functions in different quadrants?

Tip:

Always use the Pythagorean identity sin2(θ)+cos2(θ)=1\sin^2(\theta) + \cos^2(\theta) = 1 to verify trigonometric values.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Quadrants
Trigonometric Functions

Formulas

tan(𝜃) = sin(𝜃) / cos(𝜃)
sin^2(𝜃) + cos^2(𝜃) = 1
Reciprocal identities: sec(𝜃) = 1/cos(𝜃), csc(𝜃) = 1/sin(𝜃), cot(𝜃) = 1/tan(𝜃)

Theorems

Pythagorean Identity

Suitable Grade Level

Grades 10-12