View Full Version : Complex numbers and nth roots
melissa816
Dec 11, 2006, 04:29 PM
Using De Moivre's theorem and nth roots of complex numbers I need help putting z= the square root of 3 + I in trig form then finding the 5th roots of z and how to graph the roots.
Can you answer this?
asterisk_man
Dec 12, 2006, 06:28 AM
http://en.wikipedia.org/wiki/De_Moivre's_formula seems like a good source of info on De Moivre's formula.
First you need to convert z=3+i into polar form. Look here: http://en.wikipedia.org/wiki/Polar_coordinate_system#Converting_between_polar_a nd_Cartesian_coordinates
Graphing the result should be easy. Your answer should be a complex number, graph the point with the real part as the x coordinate and the imaginary part as the y coordinate.
Ask any questions if you don't understand something or want someone to review what you have done.
Thanks!
Capuchin
Dec 12, 2006, 06:32 AM
Complex coordinates are delicious! Mmmm!
Elisha Grey
Jan 18, 2007, 10:56 AM
z = 3 + I = sqrt (10) e^(I arc tan(1/3)) = 10^(1/2) e^(I arc tan(1/3)), so sqrt z =
10^(1/4) e^(I(1/2)arc tan(1/3)).