Re: Sqrt of complex number

*To*: mathgroup at smc.vnet.net*Subject*: [mg126642] Re: Sqrt of complex number*From*: "Dave Snead" <dsnead6 at charter.net>*Date*: Mon, 28 May 2012 05:10:39 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <201205270842.EAA17817@smc.vnet.net>

Use Solve to get both answers: Solve[z^2==3-4I,z] {{z->-2+I},{z->2-I}} Cheers, Dave Snead -----Original Message----- From: Jacare Omoplata Sent: Sunday, May 27, 2012 1:42 AM To: mathgroup at smc.vnet.net Subject: [mg126642] Sqrt of complex number Hi, When I try to find the square root of of a complex number, I get only one answer. In[1]:= Sqrt[3-4 I] Out[1]= 2-I But -2+I is an answer as well. In[2]:= (-2+I)^2 Out[2]= 3-4 I Why does Mathematica give the first answer and not the second? Does it choose the answer with the positive real number? Is there any way I can get both answers? Or do I just have to remember that the negative of the given answer is also an answer? Thanks.

**References**:**Sqrt of complex number***From:*Jacare Omoplata <walkeystalkey@gmail.com>