Math Problem Statement

Suppose that  θ  is an acute angle of a right triangle and that  sec(θ)=2. Find  cot(θ)  and  cos(θ).

Solution

Given that θ\theta is an acute angle of a right triangle and sec(θ)=2\sec(\theta) = 2, we can find cot(θ)\cot(\theta) and cos(θ)\cos(\theta) using trigonometric identities.

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)}

Given sec(θ)=2\sec(\theta) = 2, we can solve for cos(θ)\cos(\theta):

cos(θ)=1sec(θ)=12\cos(\theta) = \frac{1}{\sec(\theta)} = \frac{1}{2}

So, cos(θ)=12\cos(\theta) = \frac{1}{2}.

Step 2: Find cot(θ)\cot(\theta)

To find cot(θ)\cot(\theta), we need to determine sin(θ)\sin(\theta), and then use the identity cot(θ)=cos(θ)sin(θ)\cot(\theta) = \frac{\cos(\theta)}{\sin(\theta)}.

We can use the Pythagorean identity sin2(θ)+cos2(θ)=1\sin^2(\theta) + \cos^2(\theta) = 1 to find sin(θ)\sin(\theta):

sin2(θ)+(12)2=1\sin^2(\theta) + \left( \frac{1}{2} \right)^2 = 1

sin2(θ)+14=1\sin^2(\theta) + \frac{1}{4} = 1

sin2(θ)=114=34\sin^2(\theta) = 1 - \frac{1}{4} = \frac{3}{4}

sin(θ)=34=32\sin(\theta) = \sqrt{\frac{3}{4}} = \frac{\sqrt{3}}{2}

Now, using cot(θ)=cos(θ)sin(θ)\cot(\theta) = \frac{\cos(\theta)}{\sin(\theta)}:

cot(θ)=1232=13=33\cot(\theta) = \frac{\frac{1}{2}}{\frac{\sqrt{3}}{2}} = \frac{1}{\sqrt{3}} = \frac{\sqrt{3}}{3}

Final Answer:

  • cos(θ)=12\cos(\theta) = \frac{1}{2}
  • cot(θ)=33\cot(\theta) = \frac{\sqrt{3}}{3}

Would you like further details or explanations?

Here are 5 related questions for practice:

  1. If sin(θ)=12\sin(\theta) = \frac{1}{2}, what is sec(θ)\sec(\theta)?
  2. Given tan(θ)=12\tan(\theta) = \frac{1}{2}, find cot(θ)\cot(\theta).
  3. If cos(θ)=22\cos(\theta) = \frac{\sqrt{2}}{2}, what is sin(θ)\sin(\theta)?
  4. How do you calculate csc(θ)\csc(\theta) if sin(θ)=35\sin(\theta) = \frac{3}{5}?
  5. Given that cot(θ)=2\cot(\theta) = 2, find tan(θ)\tan(\theta).

Tip: Remember, secant and cosine are reciprocal trigonometric functions!

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Acute Angles
Trigonometric Identities

Formulas

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

Theorems

Pythagorean Identity
Reciprocal Trigonometric Functions

Suitable Grade Level

Grades 10-12