Answer:
C) Sin 2theta = root3/2, cos 2theta = 1/2
Step-by-step explanation:
If theta is between 0 degrees and 90 degrees, that means it's in the 1st quadrant.
If you look at a labeled unit circle, the only value where sin (y-value) of theta is at pi/6 radians. That means, theta equals pi/6. So 2theta is just pi/6 * 2 which is pi/3. Sin (pi/3) is equal to root3/2.
We know 2theta is pi/3, so the cos (x-value) of 2theta on a labeled unit circle is 1/2, which means cos 2theta is 1/2.
