Question 205743:  find all solutions of the equation z^2 = -6 + 8i 
 Answer by stanbon(75887)      (Show Source): 
You can  put this solution on YOUR website! find all solutions of the equation z^2 = -6 + 8i 
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z = sqrt(-6 + 8i) 
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Convert to trig form: 
r = sqrt(6^2+8^2) = 10 
theta = arctan(8/-6) = -53.13; 
But z^2 is in the 2nd quadrant so theta = -53.13+180 = 126.87 
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z = sqrt(10)(cis(126.87+360n)/2) 
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let n = 0, then z = sqrt(10)(cis(63.435)) 
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let n = 1, then z = sqrt(10)(cis(243.435) 
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In Rectangular form 
For n=0 
x = sqrt(10)cos(63.435) = 1.414 or sqrt(2) 
y = sqrt(10)sin(63.435) = 2.828 
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For n = 1 
x = sqrt(10)cos(243.435) = -sqrt(2) 
y = sqrt(10)sin(243.435) = -2.828... 
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Cheers, 
Stan H. 
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