Question

Find cos(2115°) and sin(2115°). Identify the measure of the reference angle.

Answer 1

Answer:

Cos(2115°) =1/√2

Sin(2115°) = -1/√2

Step-by-step explanation:

We have to find the values of Cos (2115°) and Sin (2115°).

Now, 2115° can be written as (23×90°+ 45°).

Therefore, the angle 2115° lies in the 4th quadrant where Cos values are positive and Sin values are negative.

Hence, Cos (2115°) = Cos(23×90° +45°) =Sin 45° {Since 23 is an odd number, so the CosФ sign will be changed to SinФ} =1/√2 (Answer)

Again, Sin (2115°) = Sin(23×90° +45°) = -Cos 45° {Since 23 is an odd number, so the SinФ sign will be changed to CosФ} = -1/√2 (Answer)

Now, the required reference angle is 45°. (Answer)