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Find the exact values of $sin( heta)$ and $cos( heta)$ for $ heta = frac{3pi}{4}$ using the unit circle.

Answer 1

Abigail Nelson

Ava Martin

To find the exact values of $\sin(\theta)$ and $\cos(\theta)$ for $\theta = \frac{3\pi}{4}$, we can use the unit circle.

First, note that $\theta = \frac{3\pi}{4}$ is in the second quadrant. In the unit circle, the angle $\frac{3\pi}{4}$ corresponds to $135^\circ$.

For angles in the second quadrant, the sine value is positive and the cosine value is negative. The reference angle for $\frac{3\pi}{4}$ is $\frac{\pi}{4}$ (or $45^\circ$), where $\sin(\frac{\pi}{4}) = \frac{\sqrt{2}}{2}$ and $\cos(\frac{\pi}{4}) = \frac{\sqrt{2}}{2}$.

Therefore, $\sin(\frac{3\pi}{4}) = \sin(\frac{\pi}{4}) = \frac{\sqrt{2}}{2}$ and $\cos(\frac{3\pi}{4}) = -\cos(\frac{\pi}{4}) = -\frac{\sqrt{2}}{2}$.

So, the exact values are $\sin(\frac{3\pi}{4}) = \frac{\sqrt{2}}{2}$ and $\cos(\frac{3\pi}{4}) = -\frac{\sqrt{2}}{2}$.

Answer 2

Alex Thompson

Christopher Garcia

To determine $sin( heta)$ and $cos( heta)$ for $ heta = frac{3pi}{4}$ using the unit circle:

1. Recognize that $ heta = frac{3pi}{4}$ falls in the second quadrant.

2. In the second quadrant, $sin( heta)$ remains positive, and $cos( heta)$ is negative.

3. The reference angle is $frac{pi}{4}$, with known values $sin(frac{pi}{4}) = frac{sqrt{2}}{2}$ and $cos(frac{pi}{4}) = frac{sqrt{2}}{2}$.

4. Thus, $sin(frac{3pi}{4}) = frac{sqrt{2}}{2}$ and $cos(frac{3pi}{4}) = -frac{sqrt{2}}{2}$.

Therefore, $sin(frac{3pi}{4}) = frac{sqrt{2}}{2}$, $cos(frac{3pi}{4}) = -frac{sqrt{2}}{2}$.

Answer 3

Amelia Mitchell

Sophia Williams

Using the unit circle for $ heta = frac{3pi}{4}$:

1. The angle is in the second quadrant.

2. Reference angle is $frac{pi}{4}$.

3. Hence, $sin(frac{3pi}{4}) = frac{sqrt{2}}{2}$ and $cos(frac{3pi}{4}) = -frac{sqrt{2}}{2}$.