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Is the sqrt( -1) = i , or plus-minus i

  1. Nov 1, 2008 #1
    When I am solving an equation and I take the sqrt of both sides, one of which is -1.

    Do I put i, or plusminus i ?
  2. jcsd
  3. Nov 1, 2008 #2


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    It's just [itex]i[/itex] (although engineers use [itex]j[/itex] just to be obstinate)
  4. Nov 1, 2008 #3


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    sqrt(-1) is i but the solution to x2 = 1 is +1 /-1
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