z=−2+8iFind the angle θ (in radians) that z makes in the complex plane. Round your answer, if necessary, to the nearest thousandth. Express θ between −π and π.θ=
Q. z=−2+8iFind the angle θ (in radians) that z makes in the complex plane. Round your answer, if necessary, to the nearest thousandth. Express θ between −π and π.θ=
Identify Real and Imaginary Parts: To find the angle θ that the complex number z=−2+8i makes with the positive real axis in the complex plane, we need to calculate the argument of z. The argument of a complex number is the angle formed by the radius (line from the origin to the point) and the positive x-axis. The argument can be found using the arctan function, which is the inverse of the tangent function. The formula to find the argument of a complex number a+bi is θ=arctan(b/a), where a is the real part and b is the imaginary part of the complex number.
Calculate Argument using Arctan: First, we identify the real part a and the imaginary part b of the complex number z=−2+8i. Here, a=−2 and b=8.
Determine Quadrant and Adjust Angle: Next, we calculate the argument θ using the arctan function: θ=arctan(b/a)=arctan(8/(−2))=arctan(−4). Since the complex number is in the second quadrant (because the real part is negative and the imaginary part is positive), the angle should be in the range (π/2,π).
Calculate Final Angle: Using a calculator, we find that arctan(−4)≈−1.3258 radians. However, since the angle is in the second quadrant, we need to add π to this value to get the angle in the correct range. Therefore, θ=−1.3258+π.
Verify Angle Range: Calculating the value of θ, we get θ≈−1.3258+3.1416≈1.8158 radians.
Verify Angle Range: Calculating the value of θ, we get θ≈−1.3258+3.1416≈1.8158 radians.We check to make sure that our final answer is within the range −π to π. Since 1.8158 is between −π and π, our answer is in the correct range.
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