Let point (a, b) be on a unit circle.
If (a, b) has a rotation of r degrees, then which of the following is not correct.
cos(-r) = -a
cos(r) = a
sin(-r) = -a
sin(r) = -a
sin(r) = b

The incorrect statements are:

Consider any angle in standard position together with a unit circle. The terminal side will intersect the circle at some point (x, y) .

Let the unit circle moves in the counterclockwise direction until the angle that is formed between our position, the origin, and the positive x-axis is equal to θ.

The y-coordinate of this point is always equal to the sine of the angle, and the x-coordinate of this point is always equal to the cosine of the angle.

That is  

sin θ= y

cosθ = x

Now, we have point (a, b) be on a unit circle.

If (a, b) has a rotation of r degrees.

Then

sin(-r) = -a,

sin(r) = -a is equal to the x-coordinate.

Therefore they are incorrect.

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(C) sin(-r) = -a

(D) sin(r) = -a

Explanation:

The unit circle definition allows us to extend the domain of sine and cosine to all real numbers. The process for determining the sine/cosine of any angle θ is as follows:

Starting from (1,0) move along the unit circle in the counterclockwise direction until the angle that is formed between your position, the origin, and the positive x-axis is equal to θ.

In the question, sin(-r) = -a and sin(r) = -a is equal to the x-coordinate, thus they are not correct.

An image is attached for reference.

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step-by-step explanation: