[R] sqrt(-x) vs. -x^0.5

Rolf Turner rolf.turner at xtra.co.nz
Thu Mar 22 00:37:06 CET 2012

On 22/03/12 12:17, Sarah Goslee wrote:
> It's order of operations, and a good reason to always use
> parentheses: which is evaluated first, the unary minus or
> the raising-to-powers?
> (-4)^0.5
> -(4^0.5)
> sqrt(-4)
> -sqrt(4)

If the OP *really* wants the square root of -4 he could do
sqrt(-4+0i) or (-4+0i)^0.5 (and get 0+2i in either case).


         Rolf Turner

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