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=(−45,411)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=(−45,411)Answer:
Identify Coordinates: Identify the coordinates of point P on the unit circle.The given point P has coordinates (−5/4,11/4). Since the unit circle has a radius of 1, these coordinates correspond to (cos(θ),sin(θ)) for some angle θ in standard position.
Determine Quadrant: Determine the quadrant in which the angle θ lies.The x-coordinate is negative and the y-coordinate is positive, which means the point P lies in the second quadrant.
Calculate Reference Angle: Calculate the reference angle θ′ using the given coordinates.The reference angle θ′ is found by taking the inverse cosine (arccos) of the absolute value of the x-coordinate of P. However, since we are in the second quadrant, we need to use the y-coordinate to find the reference angle using the inverse sine (arcsin) function.θ′=arcsin(11/4)
Actual Reference Angle: Calculate the actual value of the reference angle θ′.θ′=arcsin(11/4)≈arcsin(0.825)Using a calculator, we find:θ′≈55.7 degrees
Determine Actual Angle: Determine the actual angle θ based on the reference angle θ′ and the quadrant in which θ lies.Since θ is in the second quadrant, we calculate θ as:θ=180 degrees−θ′θ=180 degrees−55.7 degrees
Calculate Final Angle: Calculate the final value of θ.θ=180 degrees−55.7 degrees≈124.3 degrees
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