At Westonci.ca, we connect you with the best answers from a community of experienced and knowledgeable individuals. Our platform connects you with professionals ready to provide precise answers to all your questions in various areas of expertise. Get quick and reliable solutions to your questions from a community of experienced experts on our platform.

Consider this equation:

[tex]\cos (\theta)=\frac{\sqrt{11}}{5}[/tex]

If [tex]\theta[/tex] is an angle in quadrant [tex]I[/tex], what is the value of [tex]\sin (\theta)[/tex]?

A. [tex]\frac{\sqrt{14}}{5}[/tex]
B. [tex]\frac{\sqrt{154}}{11}[/tex]
C. [tex]-\frac{\sqrt{184}}{11}[/tex]
D. [tex]-\frac{\sqrt{14}}{5}[/tex]

Sagot :

To determine the value of [tex]\(\sin(\theta)\)[/tex] given that [tex]\(\cos(\theta) = \frac{\sqrt{11}}{5}\)[/tex] and [tex]\(\theta\)[/tex] is an angle in quadrant I, we can use the Pythagorean identity. This identity states that:

[tex]\[ \sin^2(\theta) + \cos^2(\theta) = 1 \][/tex]

We are given [tex]\(\cos(\theta) = \frac{\sqrt{11}}{5}\)[/tex]. First, we will square [tex]\(\cos(\theta)\)[/tex]:

[tex]\[ \cos^2(\theta) = \left( \frac{\sqrt{11}}{5} \right)^2 = \frac{11}{25} \][/tex]

Next, we use the Pythagorean identity to find [tex]\(\sin^2(\theta)\)[/tex]:

[tex]\[ \sin^2(\theta) = 1 - \cos^2(\theta) = 1 - \frac{11}{25} = \frac{25}{25} - \frac{11}{25} = \frac{14}{25} \][/tex]

Now, we need to find the value of [tex]\(\sin(\theta)\)[/tex]:

[tex]\[ \sin(\theta) = \sqrt{\sin^2(\theta)} = \sqrt{\frac{14}{25}} = \frac{\sqrt{14}}{5} \][/tex]

Since [tex]\(\theta\)[/tex] is in quadrant I, both [tex]\(\sin(\theta)\)[/tex] and [tex]\(\cos(\theta)\)[/tex] are positive. Therefore, the value of [tex]\(\sin(\theta)\)[/tex] is:

[tex]\[ \sin(\theta) = \frac{\sqrt{14}}{5} \][/tex]

So the correct answer is:

A. [tex]\(\frac{\sqrt{14}}{5}\)[/tex]