Answer:
To find the exact values of the sine and cosine of 2 theta, we can use the trigonometric identities that relate these functions to the sine and cosine of theta.Since theta lies in quadrant IV, we know that the cosine of theta is negative. We can use the identity cos(theta) = sin(pi/2 - theta) to find the sine of theta:sin(theta) = sin(pi/2 - theta)
= -sin(theta)Solving this equation for sin(theta), we find that sin(theta) = -2/5.To find the cosine of 2 theta, we can use the identity cos(2 theta) = 1 - 2sin^2(theta):cos(2 theta) = 1 - 2sin^2(theta)
= 1 - 2(-2/5)^2
= 1 + 8/25
= 9/25To find the sine of 2 theta, we can use the identity sin(2 theta) = 2sin(theta)cos(theta):sin(2 theta) = 2sin(theta)cos(theta)
= 2(-2/5)(-cos(theta))
= 4/5cos(theta)Thus, the exact values of the sine and cosine of 2 theta are sin(2 theta) = 4/5cos(theta) and cos(2 theta) = 9/25.
Explanation: