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=(46,−410)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=(46,−410)Answer:
Calculate Tangent Ratio: To find the angle of the terminal side through the point P on the unit circle, we need to use the inverse trigonometric functions. Since we have both the x-coordinate (cosine value) and the y-coordinate (sine value), we can use the arctangent function, which gives us the angle whose tangent is the ratio of the y-coordinate to the x-coordinate.
Use Arctangent Function: First, we calculate the tangent of the angle, which is the ratio of the y-coordinate to the x-coordinate of the point P. tan(θ)=xy=(6)/(4)−(10)/(4) tan(θ)=−610 tan(θ)=−610 tan(θ)=−35
Consider Quadrant: Next, we use the arctangent function to find the angle whose tangent is −35. However, since the arctangent function only gives us the principal value (between −90 degrees and 90 degrees), we need to consider the quadrant in which the point P lies to find the correct angle in the range [0,360) degrees.
Find Angle in Radians: The point P has a positive x-coordinate and a negative y-coordinate, which places it in the fourth quadrant. The arctangent of a negative number is also negative, which corresponds to an angle in the fourth quadrant. Therefore, we can use the arctangent function directly to find the angle in the fourth quadrant.θ=arctan(−35)
Convert to Degrees: Using a calculator to find the arctan(−5/3), we get an angle in radians. To convert it to degrees, we multiply by 180/π.θ=arctan(−5/3)×(180/π)
Find Coterminal Angle: After performing the calculation, we find that the angle is approximately −58.3 degrees. However, since we want the angle in the range [0,360) degrees, we add 360 degrees to the negative angle to find the positive coterminal angle.θ=−58.3+360θ=301.7 degrees
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