Math Problem Statement

1. Use the cofunction identities to find the measure of the acute angle ϕ. sec(ϕ) = csc(42°) [Write just the number, not the degree symbol] 2. Which of the following are correct about the triangle shown below and the trigonometric functions of θ?

Solution

Question 1: Using Cofunction Identities

We are given: sec(ϕ)=csc(42)\sec(\phi) = \csc(42^\circ) Using the cofunction identity: sec(ϕ)=csc(90ϕ)\sec(\phi) = \csc(90^\circ - \phi) This implies: ϕ=9042\phi = 90^\circ - 42^\circ Thus: ϕ=48\phi = 48 Answer for Question 1: 48


Question 2: Trigonometric Functions for Triangle

We have a right triangle with:

  • Hypotenuse = 10
  • One leg = 6 (adjacent to angle θ\theta)
  • To find the opposite side, apply the Pythagorean theorem: Opposite side=10262=10036=64=8\text{Opposite side} = \sqrt{10^2 - 6^2} = \sqrt{100 - 36} = \sqrt{64} = 8

Now, compute the trigonometric functions:

  1. sin(θ)=oppositehypotenuse=810=45\sin(\theta) = \frac{\text{opposite}}{\text{hypotenuse}} = \frac{8}{10} = \frac{4}{5} ✔️ (Correct)

  2. cos(θ)=adjacenthypotenuse=610=35\cos(\theta) = \frac{\text{adjacent}}{\text{hypotenuse}} = \frac{6}{10} = \frac{3}{5} ✔️ (Correct)

  3. tan(θ)=oppositeadjacent=86=43\tan(\theta) = \frac{\text{opposite}}{\text{adjacent}} = \frac{8}{6} = \frac{4}{3}

    • The option says tan(θ)=34\tan(\theta) = \frac{3}{4}, which is incorrect
  4. csc(θ)=1sin(θ)=54\csc(\theta) = \frac{1}{\sin(\theta)} = \frac{5}{4}

    • The option says csc(θ)=43\csc(\theta) = \frac{4}{3}, which is incorrect
  5. sec(θ)=1cos(θ)=106=53\sec(\theta) = \frac{1}{\cos(\theta)} = \frac{10}{6} = \frac{5}{3}

    • The option says sec(θ)=54\sec(\theta) = \frac{5}{4}, which is incorrect
  6. cot(θ)=1tan(θ)=34\cot(\theta) = \frac{1}{\tan(\theta)} = \frac{3}{4} ✔️ (Correct)


Correct Options:

  • sin(θ)=45\sin(\theta) = \frac{4}{5}
  • cos(θ)=35\cos(\theta) = \frac{3}{5}
  • cot(θ)=34\cot(\theta) = \frac{3}{4}

Would you like more details or further explanations? 😊

5 Related Questions:

  1. How are cofunction identities derived from right triangles?
  2. Can you explain how to find missing triangle sides using trigonometry?
  3. How do reciprocal trigonometric functions relate to primary functions?
  4. What are the common mistakes when applying the Pythagorean theorem?
  5. How do unit circle values help with trigonometric identities?

Tip:

When unsure about trigonometric ratios, quickly sketch the triangle to visualize opposite, adjacent, and hypotenuse relationships—it simplifies the process!

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Cofunction Identities
Right Triangle Ratios

Formulas

sec(ϕ) = csc(90° - ϕ)
Pythagorean theorem: a² + b² = c²
sin(θ) = opposite / hypotenuse
cos(θ) = adjacent / hypotenuse
tan(θ) = opposite / adjacent
csc(θ) = 1 / sin(θ)
sec(θ) = 1 / cos(θ)
cot(θ) = 1 / tan(θ)

Theorems

Cofunction Theorem
Pythagorean Theorem

Suitable Grade Level

Grades 9-11