Re: Bug in Solve?
- To: mathgroup at smc.vnet.net
- Subject: [mg102990] Re: Bug in Solve?
- From: Simon <simonjtyler at gmail.com>
- Date: Thu, 3 Sep 2009 07:11:12 -0400 (EDT)
- References: <h7l8rh$35s$1@smc.vnet.net>
Hi tonysin, this type of equation is quite famous historically, look for Rafael Bombelli in http://math.fullerton.edu/mathews/n2003/ComplexNumberOrigin.html. All though there are complex numbers in the solution, all imaginary parts cancel to yield a real result. You can check this by looking at the numerics, In[1]:= Solve[x^3-15 x+2==0]; %//N Out[2]= {{x->3.80451-4.44089*10^-16 I},{x->-3.938+0. I},{x- >0.133492+4.44089*10^-16 I}} which is real up to machine precision. Simon