Q. u=(−4,−3)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 Slope: To find the direction angle of the vectoru=(−4,−3), 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) of the slope of the vector, which is the ratio of its y-component to its x-component. The formula to find the direction angle is θ=tan−1(xy).
Use Arctangent Function: First, we calculate the slope of the vector by dividing its y-component by its x-component. For u=(−4,−3), the slope is (−3)/(−4)=3/4.
Adjust for Quadrant: Next, we use the arctangent function to find the angle that corresponds to this slope. However, since the vector is in the third quadrant (both x and y components are negative), the angle given by the arctangent function will be in the fourth quadrant. We need to add 180∘ to this angle to get the correct direction angle in the third quadrant.θ=tan−1(43)+180∘
Calculate Arctangent: Now, we calculate the arctangent of 43 using a calculator.θ=tan−1(43)≈36.87∘
Add 180°: Finally, we add 180° to the angle we found to get the direction angle in the correct quadrant.θ=36.87°+180°θ≈216.87°
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