Double-angle and half-angle identiies [see attachment] question2

The double angle identity for cosine is

so the half angle identity is

We picked the negative sign because our angle is in the second quadrant, negative cosine.

I used the identity

I substituted in there cosine of 30 degrees

Looks like choice d

clock

step-by-step explanation:

the formula for the equation of a circle is (x – h)2+ (y – k)2 = r2, where (h, k) represents the coordinates of the center of the circle, and r represents the radius of the circle. if a circle is tangent to the x-axis at (3,0), this means it touches the x-axis at that point.