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Determine the trigonometric identity of $ sin( heta) $ using the unit circle

Answer 1

Abigail Nelson

James Taylor

To determine the trigonometric identity of $ \sin(\theta) $ using the unit circle, we start by understanding the unit circle definition:

The unit circle is a circle with a radius of $1$ centered at the origin $(0, 0)$.

For any angle $\theta$ measured from the positive x-axis, the coordinates of the point where the terminal side of $\theta$ intersects the unit circle are given by $(\cos(\theta), \sin(\theta))$.

Therefore, the identity for $\sin(\theta)$ is the y-coordinate of this intersection point:

$ \sin(\theta) = y $

Where $y$ is the y-coordinate of the intersection point.

To provide a concrete example, if $\theta = \frac{\pi}{4}$, the coordinates of the intersection point are $\left(\frac{\sqrt{2}}{2}, \frac{\sqrt{2}}{2}\right)$, so:

$ \sin\left(\frac{\pi}{4}\right) = \frac{\sqrt{2}}{2} $

Answer 2

Alex Thompson

Amelia Mitchell

To determine the trigonometric identity of $ sin( heta) $ using the unit circle, we know that the unit circle has a radius of $1$ and is centered at the origin.

For an angle $ heta$, the coordinates of the point on the unit circle are $(cos( heta), sin( heta))$.

Thus, the identity for $sin( heta)$ is:

$ sin( heta) = y $

For instance, for $ heta = frac{pi}{6}$, the point is $left(frac{sqrt{3}}{2}, frac{1}{2}
ight)$, so:

$ sinleft(frac{pi}{6}
ight) = frac{1}{2} $

Answer 3

Amelia Mitchell

John Anderson

Using the unit circle, the identity for $ sin( heta) $ is the y-coordinate of the point at angle $ heta$:

$ sin( heta) = y $

For example, if $ heta = frac{pi}{3}$, then:

$ sinleft(frac{pi}{3}
ight) = frac{sqrt{3}}{2} $