Q. u=(−7,−10)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 direction angle: To find the direction angle of the vectoru=(−7,−10), 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.
Find tangent of angle: First, we calculate the tangent of the angle θ using the y-coordinate and the x-coordinate of the vector u. The tangent of θ is given by tan(θ)=xy. For u=(−7,−10), this is tan(θ)=−7−10.
Take arctangent: Performing the division, we get tan(θ)=710. Now we need to take the arctangent of this value to find the angle θ in radians. However, since we want the angle in degrees and between 0∘ and 360∘, we will need to adjust the angle we get from the arctangent function accordingly.
Convert to degrees: Using a calculator, we find the arctangent of 710, which gives us θ in radians. To convert this to degrees, we multiply by π180. The calculator will give us an angle in the first quadrant, but since the vector has negative x and y components, the actual direction angle is in the third quadrant.
Adjust for quadrant: The angle from the arctangent function is approximately \atan(\frac{10}{7}) \approx 55.00^\circ. Since the vector is in the third quadrant, we add 180∘ to this angle to find the correct direction angle θ.
Final direction angle: Adding 180∘ to 55.00∘ gives us θ≈235.00∘. This is the direction angle of the vector u in the third quadrant, which is between 0∘ and 360∘.
More problems from Inverses of sin, cos, and tan: degrees