Q. u=(−10,7)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 Tangent Ratio: To find the direction angle of the vectoru=(−10,7), we need to calculate the angle that the vector makes with the positive x-axis. The direction angle, often denoted as θ, can be found using the arctangent function (tan−1 or atan), which gives us the angle whose tangent is the ratio of the y-coordinate to the x-coordinate of the vector.
Use Arctangent Function: First, we calculate the tangent of the angle θ using the coordinates of u. The tangent of θ is the ratio of the y-coordinate to the x-coordinate:tan(θ)=xy=(−10)7=−0.7.
Determine Quadrant: Next, we use the arctangent function to find the angle θ whose tangent is −0.7. We must be careful to place the angle in the correct quadrant. Since the x-coordinate is negative and the y-coordinate is positive, u lies in the second quadrant, where the direction angles are between 90∘ and 180∘.θ=atan(−0.7).
Calculate Direction Angle: Using a calculator, we find that: θ=atan(−0.7)≈−35.00∘.However, this angle is measured from the positive x-axis in the clockwise direction. To find the direction angle between 0∘ and 360∘, we add 180∘ to this angle because it is in the second quadrant.θ=−35.00∘+180∘=145.00∘.
Round to Nearest Hundredth: We round the direction angle to the nearest hundredth as requested: θ≈145.00∘.
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