Q. u=(9,−6)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: To find the direction angle of the vectoru=(9,−6), we need to calculate the angle that the vector makes with the positive x-axis. The direction angle θ can be found using the arctangent function, which is the inverse of the tangent function. The tangent of the angle is the ratio of the y-coordinate to the x-coordinate of the vector. However, since the y-coordinate is negative and the x-coordinate is positive, the vector lies in the fourth quadrant, and we must add 360 degrees to the arctangent of the ratio to get the angle in the range [0, 360) degrees.
Find Arctangent: First, calculate the ratio of the y-coordinate to the x-coordinate of the vector u:tan(θ)=9−6=3−2.
Calculate Angle: Next, use the arctangent function to find the angle θ that corresponds to this ratio. Remember that the arctangent function will give us an angle in the range (−90∘,90∘), so we need to adjust it for the fourth quadrant.θ=arctan(3−2).
Adjust for Quadrant: Using a calculator, we find that:θ≈arctan(3−2)≈−33.69∘.Since this angle is in the fourth quadrant, we add 360 degrees to get the direction angle in the range [0, 360) degrees.θ=−33.69∘+360∘.
Find Final Angle: Perform the addition to find the final direction angle:θ≈−33.69∘+360∘≈326.31∘.
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