Which value is a solution for the equation [tex]\cot \frac{x}{2} = -1[/tex]?

A. [tex]\frac{3\pi}{4}[/tex]
B. [tex]\frac{7\pi}{4}[/tex]
C. [tex]\frac{3\pi}{2}[/tex]
D. [tex]\frac{5\pi}{4}[/tex]



Answer :

To determine which value of [tex]\( x \)[/tex] satisfies the equation [tex]\(\cot \left( \frac{x}{2} \right) = -1\)[/tex], we need to analyze each of the given choices and check whether they satisfy the provided condition.

We will go through each option step-by-step.

1. Option A: [tex]\( x = \frac{3\pi}{4} \)[/tex]
[tex]\[ \text{Calculate} \ \frac{x}{2} = \frac{\frac{3\pi}{4}}{2} = \frac{3\pi}{8} \][/tex]
[tex]\(\cot \left( \frac{3\pi}{8} \right)\)[/tex] does not equal to -1.

2. Option B: [tex]\( x = \frac{7\pi}{4} \)[/tex]
[tex]\[ \text{Calculate} \ \frac{x}{2} = \frac{\frac{7\pi}{4}}{2} = \frac{7\pi}{8} \][/tex]
[tex]\(\cot \left( \frac{7\pi}{8} \right)\)[/tex] does not equal to -1.

3. Option C: [tex]\( x = \frac{3\pi}{2} \)[/tex]
[tex]\[ \text{Calculate} \ \frac{x}{2} = \frac{\frac{3\pi}{2}}{2} = \frac{3\pi}{4} \][/tex]
[tex]\(\cot \left( \frac{3\pi}{4} \right) = \cot \left( 135^\circ \right) = -1\)[/tex].
Thus, [tex]\(\cot \left( \frac{3\pi}{4} \right) = -1\)[/tex].

4. Option D: [tex]\( x = \frac{5\pi}{4} \)[/tex]
[tex]\[ \text{Calculate} \ \frac{x}{2} = \frac{\frac{5\pi}{4}}{2} = \frac{5\pi}{8} \][/tex]
[tex]\(\cot \left( \frac{5\pi}{8} \right)\)[/tex] does not equal to -1.

From these calculations, we can see that the only [tex]\( x \)[/tex] value that satisfies [tex]\(\cot \left( \frac{x}{2} \right) = -1\)[/tex] is:

[tex]\[ \boxed{\frac{3\pi}{2}} \][/tex]

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