Q. u=(−1,4)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: To find the direction angle of the vectoru=(−1,4), we need to calculate the angle that this 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.
Consider Quadrant: 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=(−1)4=−4
Use Arctangent Function: Next, we use the arctangent function to find the angle θ whose tangent is −4. However, we must be careful with the signs and the quadrant in which the vector lies. Since the x-coordinate is negative and the y-coordinate is positive, u lies in the second quadrant. The arctangent function will give us an angle in the fourth quadrant, so we need to add 180∘ to get the angle in the second quadrant.θ=atan(−4)+180∘
Add 180°: We calculate the arctangent of −4 using a calculator and then add 180° to find the direction angle in the second quadrant.θ≈atan(−4)+180°≈−75.96°+180°≈104.04°
Round to Nearest Hundredth: We round the direction angle to the nearest hundredth as requested. θ≈104.04∘ (rounded to the nearest hundredth)
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