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1. If [tex]\( 0^{\circ} \ \textless \ \theta \ \textless \ 90^{\circ} \)[/tex] and [tex]\( \cos \theta = \frac{11}{61} \)[/tex], find [tex]\( \cot \theta \)[/tex] using trigonometric identities.

A. [tex]\( \frac{11}{60} \)[/tex]
B. [tex]\( \frac{60}{11} \)[/tex]
C. [tex]\( \frac{11}{61} \)[/tex]
D. [tex]\( \frac{61}{11} \)[/tex]


Sagot :

To solve for [tex]\(\cot \theta\)[/tex] given that the angle [tex]\(\theta\)[/tex] lies in the range [tex]\(0^\circ < \theta < 90^\circ\)[/tex] and [tex]\(\cos \theta = \frac{11}{61}\)[/tex], we follow these steps using trigonometric identities:

1. Identify the components of the right triangle:
- We interpret [tex]\(\cos \theta = \frac{11}{61}\)[/tex] based on the definition of cosine in a right triangle:
[tex]\[ \cos \theta = \frac{\text{adjacent}}{\text{hypotenuse}}. \][/tex]
This tells us:
[tex]\[ \text{adjacent} = 11 \quad \text{and} \quad \text{hypotenuse} = 61. \][/tex]

2. Find the opposite side of the triangle using the Pythagorean theorem:
- The Pythagorean theorem states:
[tex]\[ \text{opposite}^2 + \text{adjacent}^2 = \text{hypotenuse}^2. \][/tex]
Substituting the known values:
[tex]\[ \text{opposite}^2 + 11^2 = 61^2. \][/tex]
[tex]\[ \text{opposite}^2 + 121 = 3721. \][/tex]
Solving for [tex]\(\text{opposite}^2\)[/tex]:
[tex]\[ \text{opposite}^2 = 3721 - 121 = 3600, \][/tex]
hence:
[tex]\[ \text{opposite} = \sqrt{3600} = 60. \][/tex]

3. Determine [tex]\(\cot \theta\)[/tex]:
- We use the definition of cotangent:
[tex]\[ \cot \theta = \frac{1}{\tan \theta} = \frac{\text{adjacent}}{\text{opposite}}. \][/tex]
With the values we have determined:
[tex]\[ \cot \theta = \frac{11}{60}. \][/tex]

Therefore, the correct value of [tex]\(\cot \theta\)[/tex] given [tex]\(\cos \theta = \frac{11}{61}\)[/tex] is:
[tex]\[ \frac{11}{60}. \][/tex]

The correct option is:
[tex]\[ \frac{11}{60}. \][/tex]