Math Problem Statement

Suppose that theta is an acute angle of a right triangle and that sec(0)= 5/2 Find cos(theta) and csc()

Solution

We are given that sec(θ)=52\sec(\theta) = \frac{5}{2}, and we need to find cos(θ)\cos(\theta) and csc(θ)\csc(\theta).

Step 1: Find cos(θ)\cos(\theta)

We know that the secant function is the reciprocal of the cosine function: sec(θ)=1cos(θ)\sec(\theta) = \frac{1}{\cos(\theta)} So, we can express cos(θ)\cos(\theta) as: cos(θ)=1sec(θ)=152=25\cos(\theta) = \frac{1}{\sec(\theta)} = \frac{1}{\frac{5}{2}} = \frac{2}{5}

Thus, cos(θ)=25\cos(\theta) = \frac{2}{5}.

Step 2: Find csc(θ)\csc(\theta)

We know that the cosecant function is the reciprocal of the sine function: csc(θ)=1sin(θ)\csc(\theta) = \frac{1}{\sin(\theta)} To find sin(θ)\sin(\theta), we use the Pythagorean identity: sin2(θ)+cos2(θ)=1\sin^2(\theta) + \cos^2(\theta) = 1 Substitute cos(θ)=25\cos(\theta) = \frac{2}{5}: sin2(θ)+(25)2=1\sin^2(\theta) + \left(\frac{2}{5}\right)^2 = 1 sin2(θ)+425=1\sin^2(\theta) + \frac{4}{25} = 1 sin2(θ)=1425=2525425=2125\sin^2(\theta) = 1 - \frac{4}{25} = \frac{25}{25} - \frac{4}{25} = \frac{21}{25} sin(θ)=2125=215\sin(\theta) = \sqrt{\frac{21}{25}} = \frac{\sqrt{21}}{5}

Now, we can find csc(θ)\csc(\theta): csc(θ)=1sin(θ)=521=52121\csc(\theta) = \frac{1}{\sin(\theta)} = \frac{5}{\sqrt{21}} = \frac{5\sqrt{21}}{21}

Final Answers:

  • cos(θ)=25\cos(\theta) = \frac{2}{5}
  • csc(θ)=52121\csc(\theta) = \frac{5\sqrt{21}}{21}

Do you want more details or have any questions?

Here are five related questions:

  1. What is the value of sin(θ)\sin(\theta)?
  2. How would you calculate tan(θ)\tan(\theta)?
  3. Can you determine cot(θ)\cot(\theta) given sec(θ)\sec(\theta)?
  4. What is the relationship between sec(θ)\sec(\theta) and cos(θ)\cos(\theta)?
  5. How do we use the Pythagorean identity to find sin(θ)\sin(\theta)?

Tip: When working with trigonometric identities, it's always helpful to recall the basic reciprocal relationships between the functions (like sec(θ)=1cos(θ)\sec(\theta) = \frac{1}{\cos(\theta)}).

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Right Triangle
Reciprocal Trigonometric Functions

Formulas

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

Theorems

Pythagorean Identity

Suitable Grade Level

Grades 9-12