z=−8+5iFind the angle θ (in degrees) that z makes in the complex plane.Round your answer, if necessary, to the nearest tenth. Express θ between −180∘ and 180∘.θ=□∘
Q. z=−8+5iFind the angle θ (in degrees) that z makes in the complex plane.Round your answer, if necessary, to the nearest tenth. Express θ between −180∘ and 180∘.θ=□∘
Identify parts of z: Identify the real and imaginary parts of the complex number z.z=−8+5i, where the real part is −8 and the imaginary part is 5.
Calculate argument of z: Calculate the argument of z, which is the angle θ in the complex plane.The argument of z is given by θ=arctan(real partimaginary part)=arctan(−85).
Find theta in radians: Use a calculator to find the value of theta in radians. θ=arctan(−85)≈arctan(−0.625).
Convert angle to degrees: Convert the angle from radians to degrees. θ≈arctan(−0.625)×(180/π) degrees.
Calculate angle in degrees: Calculate the angle in degrees, ensuring it is in the correct quadrant.Since the real part is negative and the imaginary part is positive, z lies in the second quadrant. The arctan function will give a negative result because the tangent is negative in the second quadrant. To find the angle in the second quadrant, we add 180 degrees to the result.θ≈arctan(−0.625)×(180/π)+180 degrees.
Perform calculation: Perform the calculation using a calculator.θ≈arctan(−0.625)×(180/π)+180≈−32.0053832+180≈147.9946168 degrees.
Round to nearest tenth: Round the answer to the nearest tenth. θ≈148.0 degrees.
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