Best Answer dark_magician_92, 05 April 2013 - 07:37 AM

Object: to prove that i < 0 ( that is, sqrt(-1) < 0 )

( .5 + sqrt(3/4)*i )^3 = (-1)^3

which means that .5 + sqrt(3/4)*i = -1

So then 1 + sqrt(3)*i = -2

sqrt(3)*i = -1

i = -1/sqrt(3)

Therefore i is a negative number. QED.