Use a Pythagorean identity to find [tex]\(\csc (\theta)\)[/tex] if [tex]\(\cot (\theta) = 4\)[/tex] and the terminal side of [tex]\(\theta\)[/tex] lies in quadrant III.

[tex]\[
\csc (\theta) = \boxed{\square}
\][/tex]



Answer :

To find [tex]\(\csc(\theta)\)[/tex] given [tex]\(\cot(\theta) = 4\)[/tex] and that the terminal side of [tex]\(\theta\)[/tex] lies in quadrant III, follow these steps:

1. Express [tex]\(\cot(\theta)\)[/tex]:
[tex]\(\cot(\theta) = \frac{\text{adjacent}}{\text{opposite}}\)[/tex].
Given [tex]\(\cot(\theta) = 4\)[/tex], we can write this ratio as:
[tex]\[ \cot(\theta) = \frac{4}{1} \][/tex]
This means the adjacent side is 4 and the opposite side is 1.

2. Adjust for quadrant III:
In quadrant III, both the x (adjacent) and y (opposite) coordinates are negative:
[tex]\[ \text{adjacent} = -4, \quad \text{opposite} = -1 \][/tex]

3. Find the hypotenuse:
Use the Pythagorean theorem to find the hypotenuse [tex]\(r\)[/tex]:
[tex]\[ r = \sqrt{(\text{adjacent})^2 + (\text{opposite})^2} = \sqrt{(-4)^2 + (-1)^2} = \sqrt{16 + 1} = \sqrt{17} \][/tex]

4. Calculate [tex]\(\csc(\theta)\)[/tex]:
[tex]\(\csc(\theta)\)[/tex] is the reciprocal of [tex]\(\sin(\theta)\)[/tex], and [tex]\(\sin(\theta)\)[/tex] is the ratio of the opposite side to the hypotenuse:
[tex]\[ \sin(\theta) = \frac{-1}{\sqrt{17}} \][/tex]
Therefore,
[tex]\[ \csc(\theta) = \frac{1}{\sin(\theta)} = \frac{\sqrt{17}}{-1} = -\sqrt{17} \][/tex]

So the exact, fully simplified value of [tex]\(\csc(\theta)\)[/tex] is:
[tex]\[ \csc(\theta) = -\sqrt{17} \][/tex]

Other Questions