Given the following point on the unit circle, find the angle, to the nearest tenth of a degree (if necessary), of the terminal side through that point, 0^{\circ} \leq \theta<360^{\circ} .P=(−511,514)Answer:
Q. Given the following point on the unit circle, find the angle, to the nearest tenth of a degree (if necessary), of the terminal side through that point, 0∘≤θ<360∘.P=(−511,514)Answer:
Identify Point Quadrant: To find the angle θ that corresponds to a point on the unit circle, we can use the inverse trigonometric functions. The point P has coordinates (−11/5,14/5). Since the x-coordinate is negative and the y-coordinate is positive, the point lies in the second quadrant.
Calculate Reference Angle: We can use the inverse tangent function to find the reference angle α, which is the acute angle to the x-axis. However, since the tangent function only gives us angles in the first and fourth quadrants, we need to adjust our approach. We can use the y-coordinate and x-coordinate to find the tangent of the reference angle α: tan(α)=∣∣xy∣∣=∣∣−11/514/5∣∣=1114.
Find Reference Angle: Now we calculate the reference angle α using the inverse tangent function: α=arctan(14/11). We use a calculator to find this angle.
Calculate Actual Angle: After calculating, we find that α≈arctan(14/11)≈51.3 degrees. This is the reference angle in the first quadrant.
Subtract Reference Angle: Since the point is in the second quadrant, we find the actual angle θ by subtracting the reference angle from 180 degrees: θ=180−α.
Subtract Reference Angle: Since the point is in the second quadrant, we find the actual angle θ by subtracting the reference angle from 180 degrees: θ=180−α. Subtracting the reference angle from 180 degrees, we get θ≈180−51.3≈128.7 degrees.
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