Q. u=(−10,−9)Find the direction angle of u. Enter your answer as an angle in degrees between 0∘ and 360∘ rounded to the nearest hundredth.θ=□∘
Calculate Ratio Arctangent: To find the direction angle of the vectoru=(−10,−9), we need to calculate the angle that this vector makes with the positive x-axis. The direction angle θ can be found using the arctangent function (also known as the inverse tangent or atan), which gives us the angle whose tangent is the ratio of the y-coordinate to the x-coordinate of the vector.
Convert Radians to Degrees: First, we calculate the arctangent of the ratio of the y-coordinate to the x-coordinate of the vector u. Since u=(−10,−9), the ratio is −10−9. Using a calculator, we find that arctan(−10−9) gives us an angle in radians.
Adjust for Quadrant: We convert the angle from radians to degrees because the question asks for the answer in degrees. To convert radians to degrees, we multiply by π180.
Perform Calculation: The calculated angle will give us the angle relative to the positive x-axis, but since both the x and y coordinates of u are negative, u lies in the third quadrant. The arctangent function will give us an angle in the first quadrant, so we need to add 180° to get the correct direction angle in the third quadrant.
Add 180 Degrees: Performing the calculation, we have θ=arctan(−10−9)×π180+180°. Using a calculator, we find that θ≈42.01°+180°.
Round to Nearest Hundredth: Adding 180° to 42.01°, we get θ≈222.01°. This is the direction angle of vector u in the third quadrant, measured counterclockwise from the positive x-axis.
Round to Nearest Hundredth: Adding 180° to 42.01°, we get θ≈222.01°. This is the direction angle of vector u in the third quadrant, measured counterclockwise from the positive x-axis.We round the direction angle to the nearest hundredth as the question asks. Therefore, the direction angle of vector u is approximately 222.01°.
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