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=□∘
Identify Formula: Identify the formula for the direction angle of a vector.The direction angle θ of a vector u=(x,y) can be found using the arctangent function: θ=arctan(y/x). However, since arctan only gives values from −90 to 90 degrees, we need to adjust the angle based on the quadrant in which the vector lies.
Calculate Arctangent: Calculate the arctangent of the y-coordinate divided by the x-coordinate.For u=(−10,7), we have x=−10 and y=7. Thus, θ=arctan(−107)=arctan(−0.7).Using a calculator, we find that arctan(−0.7)≈−35.54 degrees.
Adjust Based on Quadrant: Adjust the angle based on the quadrant.Since the x-coordinate is negative and the y-coordinate is positive, u lies in the second quadrant. In the second quadrant, we must add 180 degrees to the arctangent value to find the correct direction angle.
Add 180 Degrees: Add 180 degrees to the arctangent value.θ=−35.54 degrees +180 degrees =144.46 degrees.
Round to Nearest Hundredth: Round the direction angle to the nearest hundredth. θ≈144.46 degrees (rounded to the nearest hundredth).