[R] problem with Gauss Hermite ( x and w )

[Rui Barradas]

Hello,

> Negative powers mean they take the reciprocal and as far as I am
> concerned, real^real is just a real number.
> Am I mistaking something basic?

Yes, you are.

real^real is not necessarily real.

The most well known example is (-1)^0.5 = imaginary unit.
When you say that -2.5^(-2.4) is real you're computing the negative power of
a POSITIVE real, 2.5 then taking the result's  symmetric.

(-2.5)^(-2.4)
[1] NaN

Or
(-1)^0.5
[1] NaN
-1^0.5
[1] -1

(-1 + 0i)^0.5 # algebraically, equal to (-1)^0.5 above, but not in R
notation.
[1] 0+1i

Hope this helps,

Rui Barradas



casperyc wrote
> 
> Hi,
> 
>  I know what complex number are, but I am not sure what you meant by that?
> 
> 
> ##############CODES###########
>> 2.5^(-2.4)
> [1] 0.1109032
>> -2.5^(-2.4)
> [1] -0.1109032
> ##############CODES###########
> 
> works fine.
> 
> Negative powers mean they take the reciprocal and as far as I am
> concerned, real^real is just a real number.
> 
> Am I mistaking something basic?
> 
> Thanks.
> 
> Casper
> 


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