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z=-2-5i
Find the angle 
theta (in radians) that 
z makes in the complex plane. Round your answer, if necessary, to the nearest thousandth. Express 
theta between 
-pi and 
pi.

theta=

z=25i z=-2-5 i \newlineFind the angle θ \theta (in radians) that z z makes in the complex plane. Round your answer, if necessary, to the nearest thousandth. Express θ \theta between π -\pi and π \pi .\newlineθ= \theta=

Full solution

Q. z=25i z=-2-5 i \newlineFind the angle θ \theta (in radians) that z z makes in the complex plane. Round your answer, if necessary, to the nearest thousandth. Express θ \theta between π -\pi and π \pi .\newlineθ= \theta=
  1. Calculate Argument of z: To find the angle θ\theta, we need to calculate the argument of the complex number z=25iz=-2-5i. The argument is the angle the complex number makes with the positive x-axis in the complex plane.
  2. Determine Quadrant for Angle: The argument of a complex number a+bia+bi is given by arctan(ba)\arctan(\frac{b}{a}), but since our aa is negative and bb is negative, the angle will be in the third quadrant. We need to add π\pi to the arctan\arctan value to get the correct angle in the range of π-\pi to π\pi.
  3. Calculate Arctan Value: First, calculate the arctan value: arctan(52)\arctan(\frac{5}{2}). This is the angle in the first quadrant, but we need the angle in the third quadrant.
  4. Adjust Angle for Third Quadrant: Using a calculator, we find arctan(52)1.190\arctan(\frac{5}{2}) \approx 1.190.
  5. Add Pi to Arctan Value: Since the angle is in the third quadrant, we add π\pi to get the angle in the correct range: 1.190+π1.190 + \pi.
  6. Calculate Final Angle: Adding 1.1901.190 to π\pi gives us approximately 1.190+3.142=4.3321.190 + 3.142 = 4.332.
  7. Ensure Angle Range: However, we need to ensure the angle is between π-\pi and π\pi. Since 4.3324.332 is greater than π\pi, we subtract 2π2\pi to get the angle in the correct range.
  8. Final Angle Calculation: Subtracting 2π2\pi from 4.3324.332 gives us 4.3322×3.142=1.9524.332 - 2\times3.142 = -1.952.

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