If [tex] \csc \theta = \frac{8}{7} [/tex], which equation represents [tex] \cot \theta [/tex]?

A. [tex] \cot \theta = \frac{\sqrt{15}}{8} [/tex]
B. [tex] \cot \theta = \frac{\sqrt{15}}{7} [/tex]
C. [tex] \cot \theta = \frac{7 \sqrt{15}}{15} [/tex]
D. [tex] \cot \theta = \frac{8 \sqrt{15}}{15} [/tex]



Answer :

Certainly! Let's solve this step by step.

Given [tex]\(\csc \theta = \frac{8}{7}\)[/tex], we need to find [tex]\(\cot \theta\)[/tex].

1. Express [tex]\(\sin \theta\)[/tex] in terms of [tex]\(\csc \theta\)[/tex]:
[tex]\[ \sin \theta = \frac{1}{\csc \theta} = \frac{1}{\frac{8}{7}} = \frac{7}{8} \][/tex]

2. Use the Pythagorean identity to find [tex]\(\cos \theta\)[/tex]:
[tex]\[ \sin^2 \theta + \cos^2 \theta = 1 \][/tex]
[tex]\[ \left( \frac{7}{8} \right)^2 + \cos^2 \theta = 1 \][/tex]
[tex]\[ \frac{49}{64} + \cos^2 \theta = 1 \][/tex]
[tex]\[ \cos^2 \theta = 1 - \frac{49}{64} \][/tex]
[tex]\[ \cos^2 \theta = \frac{64}{64} - \frac{49}{64} \][/tex]
[tex]\[ \cos^2 \theta = \frac{15}{64} \][/tex]
[tex]\[ \cos \theta = \sqrt{\frac{15}{64}} = \frac{\sqrt{15}}{8} \][/tex]

3. Calculate [tex]\(\cot \theta\)[/tex] using [tex]\(\cos \theta\)[/tex] and [tex]\(\sin \theta\)[/tex]:
[tex]\[ \cot \theta = \frac{\cos \theta}{\sin \theta} \][/tex]
[tex]\[ \cot \theta = \frac{\frac{\sqrt{15}}{8}}{\frac{7}{8}} \][/tex]
Simplify the fraction:
[tex]\[ \cot \theta = \frac{\sqrt{15}}{8} \times \frac{8}{7} = \frac{\sqrt{15}}{7} \][/tex]

Thus, the equation that represents [tex]\(\cot \theta\)[/tex] is:
[tex]\[ \cot \theta = \frac{\sqrt{15}}{7} \][/tex]

Therefore, the correct choice is:
[tex]\[ \boxed{\frac{\sqrt{15}}{7}} \][/tex]